Relationship between the morphology of A-1 segment of anterior cerebral artery and anterior communicating artery aneurysms

Background: The anterior communicating artery (ACoA) is one of the most frequent sites for cerebral aneurysm. The peculiar directions of projection of aneurysms offer great challenges to clinical treatment. Objetives: To establish the relationship between morphology of A-1 segment of anterior cerebral artery (ACA) and aneurismal projection. Methods: Randomly selected digital subtraction angiography data of 264 anterior communicating artery aneurysms (ACoAA) cases and 296 cases of other cerebral vascular diseases in the same period were retrospectively analyzed. Results: Among 264 ACoAA patients, the morphology of A-1 segment showed type Ⅰa in 158 sides, type Ⅰb in 11, type Ⅱa in 35, type Ⅱb in 87, type Ⅲ in 171 and absence in 66. The morphology of A-1 segment in 296 patients with other cerebral vascular diseases displayed type Ⅰa in 195 sides, type Ⅰb in 20, type Ⅱa in 47, type Ⅱ b in 74, type Ⅲ in 217 and absence in 39. The non-visualization of A-1 segment in the group of ACoAA occurred more than in the control group (χ2=11.482, p=0.001). The classifications of ACoAAs in 264 patients were confirmed as anterior-superior type in 121 cases, anterior-inferior type in 105, complicated type in 16, posterior-inferior type in 12 and posterior-superior type in 10. The correlation between morphology of A-1 segment of ACA and classifications of ACoAA was significant (p=0.000; C=0.619, p=0.000). The direction of ACoAA was downward when the A-1 segment of ACA was Type Ⅰa or Type Ⅱa, and was upward when it was Type Ⅰb or Type Ⅱb，and was upward or downward or complicated when it was Type Ⅲ. Conclusion: The relationship between morphology of A-1 segment of ACA and classification of ACoAA is clarified in the present study, which is helpful to surgical treatment.Keywords: anterior cerebral artery; morphology of A-1 segment; projection of anterior communicating artery aneurysmAfrican Health sciences Vol 14 No. 1 March 201

Apoptosis of supraoptic AVP neurons is involved in the development of central diabetes insipidus after hypophysectomy in rats

<p>Abstract</p> <p>Background</p> <p>It has been reported that various types of axonal injury of hypothalamo-neurohypophyseal tract can result in degeneration of the magnocellular neurons (MCNs) in hypothalamus and development of central diabetes insipidus (CDI). However, the mechanism of the degeneration and death of MCNs after hypophysectomy in vivo is still unclear. This present study was aimed to disclose it and to figure out the dynamic change of central diabetes insipidus after hypophysectomy.</p> <p>Results</p> <p>The analysis on the dynamic change of daily water consumption (DWC), daily urine volume(DUV), specific gravity of urine(USG) and plasma vasopressin concentration showed that the change pattern of them was triphasic and neuron counting showed that the degeneration of vasopressin neurons began at 10 d, aggravated at 20 d and then stabilized at 30 d after hypophysectomy. There was marked upregulation of cleaved Caspase-3 expression of vasopressin neurons in hypophysectomy rats. A "ladder" pattern of migration of DNA internucleosomal fragments was detected and apoptotic ultrastructure was found in these neurons. There was time correlation among the occurrence of diabetes insipidus, the changes of plasma vasopressin concentration and the degeneration of vasopressin neurons after hypophysectomy.</p> <p>Conclusion</p> <p>This study firstly demonstrated that apoptosis was involved in degeneration of supraoptic vasopressin neurons after hypophysectomy in vivo and development of CDI. Our study on time course and correlations among water metabolism, degeneration and apoptosis of vasopressin neurons suggested that there should be an efficient therapeutic window in which irreversible CDI might be prevented by anti-apoptosis.</p

PO-271 Effects of accumulated exercise with different intensities on insulin resistance in mice

Objective The aim of this study was to investigate the effect of 8-week moderate-intensity and high-intensity accumulated exercise on insulin resistance in mice, compared with the moderate intensity continuous exercise with equal workload, which will provide an experimental reference for seeking a more reasonable and effective exercise program to break sedentary behavior and improve metabolic diseases such as IR. Methods Eighty 4-week-old C57BL/6J mice were randomly divided into normal diet group (group C) and high-fat diet group (group H), fed with different diet. At the 10th&nbsp;weekend, insulin resistance model was&nbsp;judged by OGTT curve (AUC) and&nbsp;fasting blood glucose. All mice with insulin resistance&nbsp;were randomly divided into four groups: IR&nbsp;control group (IC), IR moderate-intensity continuous exercise group (IE), IR moderate-intensity accumulated&nbsp;exercise group (IM), IR high-intensity accumulated&nbsp;exercise group (IH), retained normal diet control group (C), with 12 mice for each group. All&nbsp;groups were fed with normal feed. The three&nbsp;exercise-related group performed an 8-week’s&nbsp;treadmill exercise&nbsp;program with equal workload&nbsp;(involve preparation and relaxation activities,0°platform slope, 5 days/week). For IE group, mice run 50min&nbsp;continuously with&nbsp;the velocity&nbsp;of 11m/min. For IM group，mice exercised&nbsp;12.5&nbsp;min per session, total 4 sessions&nbsp;per&nbsp;day,&nbsp;with 3-hour’s&nbsp;interval and the velocity of&nbsp;11m/min. The IH group&nbsp;performed an alike exercise program with IM group, except the running speed (19m/min) and exercise time&nbsp;(7.5min).&nbsp;On&nbsp;the 8th&nbsp;weekend of exercise, FBG, OCTT, FINS, HOME- IR, and ISI&nbsp;were tested&nbsp;for each groups. Results 1. Compared with group C, body weight, FBG and OGTT-AUC were significantly increased in group H (P&lt;0.05 or P&lt;0.01). 76%&nbsp;mice&nbsp;were induced to insulin resistance successfully.&nbsp; 2. Before and after exercise intervention of&nbsp;8 weeks, there were no significant changes in body weight and OGTT-AUC, while the FBG was significantly increased in IC group (P&lt;0.05).&nbsp;Body weight, FBG, and OGTT-AUC significantly decreased in&nbsp;IE group, IM group and IH group&nbsp;(P&lt;0.05 or P&lt;0.01). 3.&nbsp;After 8 weeks of exercise intervention, the FBG in the IE group, IM group,&nbsp;and IH group were&nbsp;significantly lower than that in&nbsp;C group (P&lt;0.05&nbsp;or P&lt;0.01).&nbsp;Compared with the IC group, the FBG, FINS, OGTT-AUC, and HOME-IR in&nbsp;IM group, IH group and IE group were lower than those in the IC group (P&lt;0.05 or P&lt;0.01).&nbsp;Compared with the IE group, the body weight and HOME-IR index of&nbsp;IH group were significantly lower than those in IE group (P&lt;0.01). Compared with&nbsp;IH group, the HOME-IR in IH group was lower than that in&nbsp;IM group (P&lt;0.05); There was no significant difference between&nbsp;IM group and&nbsp;IE group. Conclusions 1. Chronic moderate-intensity continuous exercise, moderate-intensity accumulated&nbsp;exercise, and high-intensity accumulated&nbsp;exercise all can effectively improve the glucose metabolism and insulin resistance in IR mice. 2.Compared&nbsp;with&nbsp;moderate-intensity accumulated&nbsp;exercise and moderate-intensity continuous exercise, the high-intensity accumulated&nbsp;exercise with equal workload is more effective in reducing the body weight and improving insulin resistance&nbsp;in&nbsp;IR mice. &nbsp

Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators

Recent advances in nonlinear optics have revolutionized integrated photonics, providing on-chip solutions to a wide range of new applications. Currently, state of the art integrated nonlinear photonic devices are mainly based on dielectric material platforms, such as Si₃N₄ and SiO₂. While semiconductor materials feature much higher nonlinear coefficients and convenience in active integration, they have suffered from high waveguide losses that prevent the realization of efficient nonlinear processes on-chip. Here, we challenge this status quo and demonstrate a low loss AlGaAs-on-insulator platform with anomalous dispersion and quality (Q) factors beyond 1.5 × 10⁶. Such a high quality factor, combined with high nonlinear coefficient and small mode volume, enabled us to demonstrate a Kerr frequency comb threshold of only ∼36 µW in a resonator with a 1 THz free spectral range, ∼100 times lower compared to that in previous semiconductor platforms. Moreover, combs with broad spans (>250 nm) have been generated with a pump power of ∼300 µW, which is lower than the threshold power of state-of the-art dielectric micro combs. A soliton-step transition has also been observed for the first time in an AlGaAs resonator

Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators

We demonstrated ultra-efficient frequency comb generation in AlGaAs-on-insulator ring resonators that have a quality factor beyond 1.5*10⁶. The threshold power is as low as 36 µW

Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators

Recent advances in nonlinear optics have revolutionized integrated photonics, providing on-chip solutions to a wide range of new applications. Currently, state of the art integrated nonlinear photonic devices are mainly based on dielectric material platforms, such as Si₃N₄ and SiO₂. While semiconductor materials feature much higher nonlinear coefficients and convenience in active integration, they have suffered from high waveguide losses that prevent the realization of efficient nonlinear processes on-chip. Here, we challenge this status quo and demonstrate a low loss AlGaAs-on-insulator platform with anomalous dispersion and quality (Q) factors beyond 1.5 × 10⁶. Such a high quality factor, combined with high nonlinear coefficient and small mode volume, enabled us to demonstrate a Kerr frequency comb threshold of only ∼36 µW in a resonator with a 1 THz free spectral range, ∼100 times lower compared to that in previous semiconductor platforms. Moreover, combs with broad spans (>250 nm) have been generated with a pump power of ∼300 µW, which is lower than the threshold power of state-of the-art dielectric micro combs. A soliton-step transition has also been observed for the first time in an AlGaAs resonator