ABSTRACT
Objective To introduce a practical high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)method for the detection of seven growth hormone-releasing peptides (GHRPs)including GHRP-1,GHRP-2,GHRP-4,GHRP-5,GHRP-6,Hexarelin and Alexamorelin and two growth hormone secretagogues(GHS)including anamorelin and ipamorelin,and study the stability of these nine substances in the human urine.Method The urine samples were purified and extracted by a solid phase extraction procedure using Oasis(R) WCX column.The urine was first centrifuged and taken out 1 mL into a small column,cleaned by 5％ NH4OH and 20％ CH3CN respectively,eluated using the mixture of water and acetomitrile(1/3)with 2％ formic acid,blow-dried in the nitrogen at 35℃ and finally redissolved to be injected into the LC-MS/MS.Result The limits of detection were between 0.01～0.5 ng/mL accordingly.The spiked recoveries at the low concentration(1 ng/mL),medium concentration(2 ng/mL)and high concentration(10 ng/mL)ranged between 40％ and 76％.The intra-and interday precisions of the target substances at these three concentrations were all less than 15％.The indoor temperature,refrigeration condition and multigelation were observed to have significant impact on the anamorelin,GHRP-2,GHRP-4 and GHRP-5.Conclusion The method established in this study is simple,and its specificity and sensitivity meets the international standard and technical documents for laboratories set up by the Wworld Anti-Doping Agency.It has been applied in our routine work.Multigelation should be avoided in the transport,detection and long-term laboratory storage of urine samples.
ABSTRACT
Objective To investigate whether there existed a healthy obese subtype.Methods A total of 116 healthy subjects were recruited.They were divided into 3 groups according to BMI and metabolic disorders:40 cases of normal weight and metabolic normality (NMN),36 cases of obesity and metabolic normality (OMN) and 40 cases of obesity and metabolic abnormality (OMA).Anthropometic parameters as height,weight,waist circumference,hip circumference and blood pressure was recorded.Blood glucose,lipids,insulin,high-sensitivity C-reactive protein (hs-CRP) was detected.Body fat distribution was detected by dual-energy X-ray absorptiometry (DXA).Serum von Willebrand factor (vWF),a marker of endothelial dysfunction,were detected by ELISA.Results Both serum vWF levels in OMN group [(733.6±86.2)U/L] and OMA group[(809.2 ±46.3)U/L] are higher than that in NMN group [(466.9 ±65.3)U/L,P ＜0.05] with serum vWF level in OMA group is higher than in OMN group (P ＜ 0.05).Among android fat mass percentage (AFM％),BMI,waist height ratio,waist circumference,hs-CRP,weight,hip circumference and trunk fat mass,AFM％,BMI and hs-CRP are main influencing factors of vWF.Conclusions Endothelial dysfunction existed in obese adults regardless of their metabolic status.There is no healthy obese subtype.AFM％,BMI and hs-CRP are the main influencing factors of endothelial dysfunction.
ABSTRACT
<p><b>OBJECTIVE</b>To study the mutual interaction of vestibular afferent nervous system and vestibular efferent nervous system in vestibular compensation.</p><p><b>METHODS</b>Build up animal model of vestibular compensation by destroying single side vestibule of wistar rat. In the study the rats were divided into 3 groups: Group A 16 normal rats; Group B 15 rats, after 7 days of left vestibular damage; Group C 7 rats 3 months after left vestibular damage; and Group D 7 rats, after vestibular compensation. Electromyography of the rats was recorded and the expression of calcitonin gene relative peptide (CGRP), choline acetyltransferase (AChT) and Na-K-ATPase were investigated in efferent vestibular nervous system.</p><p><b>RESULTS</b>Electric potential activity of muscles of injury side decreased while that of the opposite side increased. In animals of vestibular compensation electric potential of bilateral musculus longus capitis at quiescent stage recovered symmetrically. CGRP positive cells of efferent vestibular nervous system increased bilaterally, and their activity enhanced, especially obvious at the acute stage. AChT positive cells of injury side of efferent vestibular nervous system decreased, but reaction degree of two sides enhanced. Reaction degree of the opposite side enhanced obviously at the stage of vestibular compensation. Expression of Na-K-ATPase mRNA of the same side was lower, but vestibular signal of the opposite side enhanced, clinically head and neck inclined obliquely by means of medial fasciculus of tractus vestibulospinalis. Months later, vestibular signal of the same side enhanced, and that of the opposite side enhanced also, clinical symptoms improved slightly. At the vestibular compensation stage, expression of Na-K-ATPase mRNA of the same side enhanced, and it was same as that of the opposite side or much higher, clinically it reached vestibular compensation.</p><p><b>CONCLUSION</b>Comprehensive effect of the above results maybe as follows: Efferent vestibular nervous system inhibited afferent signal of the opposite vestibule, and it modulated excitement of vestibular center of the same side, and it worked in the complicated mechanisms of vestibular compensation. CGRP may have facilitation function to the vestibular afferent signal of injury side. While Ach improved vestibule compensation by means of inhibition of vestibule excitement of the healthy side.</p>