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OBJECTIVE： To prepare Baicalin-loaded Polyethylene glycol-derivatized phosphatidylethanolamine （BAI@PEG-PE） nanomicelles， and to characterize it and study its cytotoxicity. METHODS： BAI@PEG-PE nanomicelles were prepared by film hydration method and their appearance characteristics were observed. The particle size， polydispersity index， Zeta potential， drug-loading amount and encapsulation efficiency of the nanomicelles were detected. Drug release of BAI raw material and BAI@PEG-PE nanomicelles in pH 7.4 phosphate buffer were compared within 1-84 h. Using coumarin 6 as fluorescent probe， the distribution of PEG-PE nanomicelles in H9c2 cardiomyocytes were observed. H9c2 cardiomyocytes were divided into model group， BAI raw material group and BAI@PEG-PE nanomicelles group. After treated with serum-free DMEM medium containing no or corresponding drugs for 0.5 h， isoproterenol was used to induce cardiomyocyte apoptosis. Nuclear morphology， cell apoptosis rate and protein expression of Bcl-2 and Bax were compared with among 3 groups. RESULTS： Prepared BAI@PEG-PE nanomicelles were uniform globular shape. The particle size was （16.7±0.8） nm， PDI was 0.11±0.01 and Zeta-potential was （－18.4±0.6） mV； drug-loading amount was （7.84±0.65）％， encapsulation efficiency was （85.7±4.9）％ （n＝3）. Accumulative release rate was 76.5％ within 84 h. BAI raw material was released completely within 24 h. PEG-PE nanomicelles could strengthen the intake of coumarin 6 in H9c2 cardiomyocytes， mainly gathering around mitochondria. Compared with model group， the apoptosis morphology of cardiomyocytes were improved significantly in BAI raw material group and BAI@PEG-PE nanomicelles group； apoptosis rate was decreased significantly； protein expression of Bcl-2 was increased significantly； protein expression of Bax was decreased significantly with statistical significance （P＜0.05 or P＜0.01）. Above effects of BAI@PEG-PE nanomicelles group were more significant （P＜0.05 or P＜0.01）. CONCLUSIONS： BAI@PEG-PE nanomicelles are prepared successfully， and show significant sustained-release effect and myocardial targeting， and can prevent cardiomyocyte apoptosis.
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Objective To investigate the improving effect of betahistine hydrochloride (BH) on the cochlear blood supply in guinea pig and the potential use in cochlear ischemia. Methods The guinea pig model of ischemic inner ear was established by ferromagnetic embolization of the target microvessels of the cochlea. A total of 10 model guinea pigs were divided into BH group and control group ( n =5 in each group). Guinea pigs in BH group were treated with 0.1% BH through gastric canal, and those in the control group with the identical volume of saline. At 24 h after treatment, the cochlear blood flow (CBF), auditory brainstem responses (ABR), ferromagnetic emboli in the microvessels of cochlear lateral wall, and the hair cell succinic dehydrogenase (SDH) activity were detected. Results CBF in 10 ears in the control group was (50?7)%, and the elevated ABR threshold was found in 7 ears (70%). Ferromagnetic emboli confirmed by carbonyl iron spheres were extensively distributed in the microvessels in the cochlear lateral wall. Spot like lesion of the outer hair cells was found in SDH stained basic membrane. However, in BH group, CBF was (81?11)%. Elevated threshold of ABR was found in only 3 ears, and the ferromagnetic emboli in the microvessles in the cochlear lateral wall were less than those in the control group. Scattered lesions of the outer hair cells were found in SDH stained basic membrane. There was significant difference in the number of deleted hair cells between the BH group and the control group. Conclusion The preliminary results indicated that BH may increase CBF and attenuate the cochlear lesion due to ischemia, resulting in partial protection of hearing.
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Objective To study the vestibular aqueduct(VA) with CT in Meniere,s disease(MD). Method The experiment consisted of three groups: normal ear group, non-MD vertigo group and MD group. VA in each group was examined with CT, and the width of the external aperture of VA was measured.Result VA in normal ear group and non-MD vertigo group was well visualized,and non-visualization rate was 9.1%. VA non-visualization rate in MD group was 75%, external aperture was narrowed in VA patients. Conclusion non-visualization or narrowing of the enterhal aperture can be considered as one of the diagnostic sings of MD.
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The interference of optokinetic nystagmus from vestibular nystagmus was evaluated in 10 patients with a pre-existing spontaneous peripheral vestibular nystagmus, and in 9 normal subjects, in whom vestibular nystagmus was induced with 10 times of 60?sec constant speed count-clockwise rotation. The examinees of both groups were all subjected to horizontal clockwise and counter-clockwise optokinetic stimulation(target speed 60?/sec, frequency 2 Hz).It was found that vestibular nystagmus exerted no significant modifying effect on the eye velocity of the slow phas? of optokinptic nystagmus and that no favourablp evid?cs was demonstrated to support the algebraic summation hypothesis.
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Objective To study the vestibular aqueduct(VA) with CT in Meniere , s disease(MD). Method The experiment consisted of three groups: normal ear group, non-MD vertigo group and MD group. VA in each group was examined with CT, and the width of the external aperture of VA was measured.Result VA in normal ear group and non MD vertigo group was well visualized,and non visualization rate was 9.1%. VA non visualization rate in MD group was 75%, external aperture was narrowed in VA patients. Conclusion non visualization or narrowing of the enterhal aperture can be considered as one of the diagnostic sings of MD.