University of Florence

About: University of Florence is a education organization based out in Florence, Toscana, Italy. It is known for research contribution in the topics: Population & Carbonic anhydrase. The organization has 27292 authors who have published 79599 publications receiving 2341684 citations. The organization is also known as: Università degli studi di Firenze & Universita degli studi di Firenze.

Late Holocene drought responsible for the collapse of Old World civilizations is recorded in an Italian cave flowstone

Abstract: A severe drought in parts of low-latitude northeastern Africa and southwestern Asia ∼4200 yr ago caused major disruption to ancient civilizations. Stable isotope, trace element, and organic fluorescence data from a calcite flowstone collected from the well-watered Alpi Apuane karst of central-western Italy indicate that the climatic event responsible for this drought was also recorded in mid-latitude Europe. Although the timing of this event coincides with an episode of increased ice-rafted debris to the subpolar North Atlantic, the regional ocean-atmosphere response seems atypical of similar Holocene ice-rafting events. Furthermore, comparison of the flowstone data with other regional proxies suggests that the most extreme part of the dry spell occurred toward the end of a longer-term climate anomaly.

Intracellular Calcium Accumulation and Responsiveness to Progesterone in Capacitating Human Spermatozoa

Abstract: Progesterone induced a rapid, long-lasting, dose- dependent increase of intracellular free calcium concentration ((Ca2+)i) in human sperm capacitated overnight. This effect was not counteracted by the cytosolic progesterone receptor antagonist RU486 (1 �mol/L) nor by the GABA-A receptor antag- onists bicuculline (10 �mol/L) and picrotoxin (50 �mol/L). Also, the rank order of potency of several progestative steroids on (Ca2+)i differed from that previously reported for uterine intra- cellular progesterone receptor or for P-GABA interaction in the central nervous system, indicating a different pathway for pro- gesterone stimulation of human sperm. Modifications of basal and progesterone-stimulated (Ca2+)i during sperm capacita- tion were also studied. A progressive, parallel increase of basal and progesterone-stimulated (Ca2+)i in capacitating spermato- zoa was found. In particular, progesterone-stimulated (Ca2+)i increased from a basal concentration of 147% ± 17% at 10 mm- utes to 327% ± 65% after 120 minutes of incubation in capaci- tating medium. This increase was well correlated with basal (Ca2+li (r = 0.93). In contrast, basal and progesterone- stimulated (Ca2+)i concentrations were constantly low in sper- matozoa incubated in noncapacitating medium. In capacitated spermatozoa, initial responsiveness to progesterone and basal (Ca2+)i was higher than in capacitating and noncapacitated samples,and remained constantthroughout the duration of the experiment.The progressive,parallelincreaseof (Ca2-f-)i and response to progesterone observed during in vitro capacitatlon ofhuman spermatozoa might be physiologically relevantinvivo duringcapacitationof sperm in the female genital tract.

Type 2 diabetes mellitus and testosterone: a meta-analysis study.

Abstract: Several studies suggest that type 2 diabetes mellitus (T2DM) is often associated with male hypogonadism. Despite the well-known link, the role of testosterone replacement therapy (TRT) in T2DM has not been completely clarified. The aim of the present study was to analyse systematically the relationship between androgen levels and T2DM by reviewing and meta-analysing available prospective and cross-sectional studies. In addition, a specific meta-analysis on the metabolic effects of TRT in available randomized clinical trials (RCTs) was performed. An extensive Medline search was performed including the following words: 'testosterone', 'type 2 diabetes mellitus' and 'males'. Of 742 retrieved articles, 37 were included in the study. In particular 28, 5 and 3 were cross-sectional, longitudinal and interventional studies, respectively. A further unpublished RCT was retrieved from http://www.clinicaltrials.gov. T2DM patients showed significantly lower testosterone plasma levels in comparison with non-diabetic individuals. Similar results were obtained when T2DM subjects with and without erectile dysfunction were analysed separately. Meta-regression analysis demonstrated that ageing reduced, while obesity increased, these differences. However, in a multiple regression model, after adjusting for age and body mass index (BMI), T2DM was still associated with lower total testosterone (TT) levels (adjusted r = -0.568; p < 0.0001). Analysis of longitudinal studies demonstrated that baseline TT was significantly lower among patients with incident diabetes in comparison with controls (HR = -2.08[-3.57;-0.59]; p < 0.001). Combining the results of RCTs, TRT was associated with a significant reduction in fasting plasma glucose, HbA1c, fat mass and triglycerides. Conversely, no significant difference was observed for total and high-density lipoprotein cholesterol, blood pressure and BMI. The meta-analysis of the available cross-sectional data suggests that T2DM can be considered independently associated with male hypogonadism. Although only few RCTs have been reported, TRT seems to improve glycometabolic control as well as fat mass in T2DM subjects.