Panel A: Representative gel blots of total and phosphorylated Akt, eNOS and AMPK in cardiomyocytes freshly isolated from young (4-month-old) or aging (12-month-old) lean (C57) and <i>ob/ob</i> mice treated with or without leptin (1.0 and 50 nM) for 4 hrs using specific antibodies; Panel B: Phosphorylation of Akt expressed as pAkt-to-Akt ratio; Panel C: Phosphorylation of eNOS expressed as peNOS-to-eNOS ratio; and Panel D: Phosphorylation of AMPK expressed as pAMPK-to-AMPK ratio.

<p>Mean ± SEM, n = 4 – 6 isolations, * p<0.05 <i>vs.</i> respective C57 group, ** p<0.05 <i>vs.</i> young C57 group, # p<0.05 <i>vs.</i> respective <i>ob/ob</i> group.</p

The leptin receptor Ob-R expression (Panel A) and phosphorylation of the leptin receptor downstream signaling molecule STAT-3 (pSTAT3, Panel B) in cardiomyocytes freshly isolated from young (4-month-old) or aging (12-month-old) lean (C57) and <i>ob/ob</i> mice treated with or without leptin (1.0 and 50 nM) for 4 hrs.

<p>Protein expression of Ob-R and pSTAT-3 was normalized to the loading control GAPDH or total STAT-3, respectively. Insets: Representative gel blots of Ob-R, pSTAT-3 and STAT-3 proteins using specific antibodies. Mean ± SEM, n = 3 – 6 isolations, * p<0.05 <i>vs.</i> respective C57 group, # p<0.05 <i>vs.</i> respective <i>ob/ob</i> group.</p

General features of young (4-month-old) or aging (12-month-old) lean C57 and <i>ob/ob</i> mice.

<p>HW  =  heart weight; LW  =  liver weight; KW  =  kidney weight; TL  =  tibial length; Mean ± SEM, * p<0.05 <i>vs.</i> corresponding young group, ** p<0.05 <i>vs.</i> corresponding C57 group, n = 13 and 14 mice for C57 and <i>ob/ob</i> groups, respectively.</p

Light microscopic images of cardiomyocytes freshly isolated from young (4-month-old) and aging (12- or 18-month-old) lean (C57) and <i>ob/ob</i> mice.

<p>200x, scale bar  = 100 µm.</p

Intracellular Ca²⁺ transient properties of cardiomyocytes freshly isolated from young (4-month-old) and aging (12- or 18-month-old) lean (C57) and <i>ob/ob</i> mice treated with or without leptin (0.5, 1.0 and 50 nM) for 4 hrs.

<p>A: Resting intracellular Ca²⁺ fluorescence intensity; B: Rise in intracellular Ca²⁺ fluorescence intensity in response to electrical stimuli; C: Single-exponential Ca²⁺ transient decay rate and D: Bi-exponential Ca²⁺ transient decay rate. Mean ± SEM, n = 36–38 cells from 3 mice per group, * p<0.05 <i>vs.</i> respective C57 group, ** p<0.05 <i>vs.</i> young C57 group, # p<0.05 <i>vs.</i> respective <i>ob/ob</i> group.</p

Cumulative survival curve (Kaplan-Meier survival plot) of male C57 lean and <i>ob/ob</i> obese mice.

<p>The cumulative survival rate was plotted against age in months. The Log rank test was performed to compare the two mouse groups (p = 0.0007). n = 26 and 16 mice for C57 and <i>ob/ob</i> mice, respectively.</p

Contractile properties of cardiomyocytes freshly isolated from young (4-month-old) and aging (12- or 18-month-old) lean (C57) and <i>ob/ob</i> mice treated with or without leptin (0.5, 1.0 and 50 nM) for 4 hrs.

<p>A: Resting cell length; B: Peak shortening (PS, normalized to cell length); C: Maximal velocity of shortening (+ dL/dt); D: Maximal velocity of relengthening (- dL/dt); E: Time-to-peak shortening (TPS); F: Time-to-90% relengthening (TR₉₀); Mean ± SEM, n = 50–53 cells from 3 mice per group, * p<0.05 <i>vs.</i> respective C57 group, ** p<0.05 <i>vs.</i> young C57 group, # p<0.05 <i>vs.</i> respective <i>ob/ob</i> group.</p

O₂⁻ production (Panel A) and <i>p</i>⁴⁷^{<b><i>phox</i></b>}<b> NADPH oxidase subunit expression (Panel B) measured by DHE fluorescence and immunoblotting, respectively, in cardiomyocytes freshly isolated from young (4-month-old) or aging (12-month-old) lean (C57) and </b><b><i>ob/ob</i></b><b> mice treated with or without leptin (0.5, 1.0 and 50 nM) for 4 hrs.</b>

<p>Insets: Representative gel blots of <i>p</i>^{47<i>phox</i>} NADPH oxidase subunit using specific anti-<i>p</i>^{47<i>phox</i>} antibody. GAPDH was used as the loading control. Mean ± SEM, n = 12–14 (Panel A) and 9–11 (Panel B) per group, * p<0.05 <i>vs.</i> respective C57 group, ** p<0.05 <i>vs.</i> young C57 group, # p<0.05 <i>vs.</i> respective <i>ob/ob</i> group.</p

Contractile properties of cardiomyocytes isolated from young (4-month-old) and aging (12-month-old) male C57 mice fed a low (10%) or high (45%) fat diet for 16 weeks.

<p>Cohorts of cardiomyocytes were treated with or without leptin (1.0 nM) for 4 hrs prior to mechanical study. A: Resting cell length; B: Peak shortening (PS, normalized to cell length); C: Maximal velocity of shortening (+ dL/dt); D: Maximal velocity of relengthening (- dL/dt); E: Time-to-peak shortening (TPS); F: Time-to-90% relengthening (TR₉₀); Mean ± SEM, n = 50–51 cells from 3 mice per group, * p<0.05 <i>vs.</i> respective low fat group, ** p<0.05 <i>vs.</i> young low fat group.</p

U–Pb dating of zircon and cassiterite from the Early Cretaceous Jiaojiguan iron-tin polymetallic deposit, implications for magmatism and metallogeny of the Tengchong area, western Yunnan, China

<p>The newly discovered Jiaojiguan deposit, a medium-scale skarn iron-tin polymetallic deposit on the Sino-Burma boundary of Yunnan Province (SW China), is spatially associated with the biotite monzonitic granite. Here, we report new <i>in situ</i> zircon LA-MC-ICP-MS U–Pb ages, trace element and Hf isotope data from the granite, and U–Pb dating ages of cassiterite from the ore bodies. In this study, we obtain a weighted mean ²⁰⁶Pb/²³⁸U age of 124.1 ± 1.4 Ma for the zircon and a ²⁰⁷Pb/²⁰⁶Pb-²³⁸U/²⁰⁶Pb intercept age of 123.8 ± 2.2 Ma for the cassiterite. The granite crystallized during the Early Cretaceous, with zircons exhibiting <i>ε</i>Hf(<i>t</i>) values from −5.8 to −0.6 and two-stage Hf model ages (T_DM2) of 1.21–1.54 Ga. The close temporal and spatial links between pluton emplacement and ore-forming events suggest that magmatic-hydrothermal events were the key factors that triggered the genesis of the iron-tin polymetallic deposits in the area. Regional geochronological data show that tin mineralization took place three times during the Cretaceous–Palaeogene in the Tengchong block due to re-melting of the underlying supposed Proterozoic (1.5 ± 0.5 Ga) Sn-rich strata/materials. Compared with those in the Bangong–Nujiang metallogenic belt (BNMB), we propose that the Cretaceous iron-tin polymetallic mineralization events in Tengchong–Baoshan closely resemble those of the Bangong–Nujiang belt in northern Tibet, both of which have experienced similar tectono-magmatic-metallogenic histories since the Mesozoic.</p