A new method for the determination of peptide antibiotics in sediment from aquaculture environment by high performance liquid chromatography-tandem mass spectrometry was developed. The target analytes in sediments were ultrasonically extracted twice with citrate buffer solution and methol mixture (3∶ 4, V/ V), followed by complexation with 0. 5 g of Na2 EDTA, purification with 5 mL of methyl isobutyl ketone, and clean-up with HLB-SPE column. The analytes were separated on a MGII C18 column by gradient elution with 0. 1% formaic acid-0. 1% formaic acid acetonitrile as mobile phase, detected in multiple reaction monitoring (MRM) with electrospray ionization (ESI) under positive ion mode, and quantified by external standard method. The calibration curves were linear (R2 >0. 999) over a concentration range of 10 -10000μg / L for colistin and bacitracin and 4-4000 μg / L for virginiamycin M1 . The limits of detection (S / N = 3) were 5 μg / kg for colistin and bacitracin and 2 μg / kg for virginiamycin M1 . The limits of quantification (S / N=10) was 10 μg / kg for colistin and bacitracin and 4 μg / kg for virginiamycin M1 . At three spiked levels, the recoveries ranged from 79. 7% to 91. 6% (RSD=1. 9% -10. 8% ), showing high sensitivity, good reproducibility and wide applicability.

Objective To investigate the correlation between blood pressure rhythm and left ventricular structure and function in elderly hypertensive patients. Methods A total of 147 elderly patients with high blood pressure in the First Hospital of Longyan Affiliated to Fujian Medical University were selected. All the patients received 24h ambulatory blood pressure examination. According to the rhythm of blood pressure, the patients were divided into the dipper blood pressure group,the-non dipper type blood pressure group and the anti-dipper type blood pressure group. All patients were examined by echocardiography. Results According to the results of 24h dynamic blood pressure,the type of dipper blood pressure accounted for 11.56% (17 cases) in 147 elderly patients, non-dipper type blood pressure type accounted for 51.02% (75 cases),and the anti-dipper type of blood pressure type accounted for 37.41% (55 cases).The ventricular septal thickness(IVST),left ventricular diastolic inner diameter (LVEDD),left atrium inner diameter(LAD),left ventricle posterior wall thickness( LVPWT) and left ventricle mass index(LVMI) of the non-dipper blood pressure group were (10.56 ± 1.51)mm,(50.17 ± 4.31) mm,(34.65 ± 5.78)mm,(9.26 ± 0.98)mm,(102.31 ± 23.23)g/m2 ,respectively.The IVST,LVEDD,LAD,LVPWT and LVMI of the anti-dipper blood pressure group were (10.51 ± 1.86)mm,(50.20 ± 3.66)mm,(36.96 ± 4.22)mm,(9.42 ± 0.99)mm,(110.47 ± 31.96) g/m2 ,respectively.The IVST,LVEDD,LAD,LVPWT and LVMI of the dipper blood pressure group were (9.53 ± 1.53) mm,(47.59 ± 2.27) mm,(30.47 ± 4.17) mm,(8.88 ± 1.12) mm,(84.98 ± 15.48) g/m2 , respectively. The differences of IVST, LVEDD, LAD, LVPWT and LVMI in the three groups were statistically significant(F=1.172,3.428,1.006,0.135,all P<0.05).The maximum blood flow velocity in early diastolic period of mitral valve blood flow spectrum(E peak)/maximum blood flow velocity in late diastolic period(A peak)(E/A)of the non-dipper blood pressure group and anti-dipper blood pressure group were (0.89 ± 0.30), (0.80 ± 0.28),respectively,which was significantly lower than that of dipper blood pressure group [(1.35 ± 0.63)] (t= -2.890,-3.440,all P<0.05).The left ventricular ejection score(LVEF) of the anti-dipper blood pressure group was (65.31 ± 6.74)% ,which was significantly lower than that of the dipper blood pressure group[(70.12 ± 10.76)% ],the difference was statistically significant(t= -2.209,P<0.05).The 24 h mean systolic pressure,24 h mean diastolic pressure and daytime mean diastolic pressure in the three groups of dynamic blood pressure parameters had no statistically significant differences (all P>0.05).The average daytime systolic pressure in the dipper blood pressure group was (143.06 ± 13.70) mmHg,which was higher than that in the non-dipper blood pressure group [(133.25 ± 13.28)mmHg] and anti-dipper blood pressure group[(131.16 ± 12.26)mmHg],the differences were statistically significant(t= -2.734,-3.401,all P <0.05).The mean evening systolic pressure and the average nocturnal diastolic pressure of anti -dipper blood pressure group were ( 139.04 ± 15.01 ) mmHg and ( 80.18 ± 10.29) mmHg, respectively, which were higher than those of the dipper and non - dipper blood pressure group [(123.24 ± 14.49)mmHg and (72.24 ± 7.97) mmHg,(127.40 ± 13.30) mmHg,(73.45 ± 11.43) mmHg],the differences were statistically significant ( t =3. 822, 4. 666, 2. 919, 3. 456, all P <0. 05 ). LVMI was positively correlated with age,body mass index(BMI),low density lipoprotein( LDL-C),daytime average systolic pressure, night average systolic pressure,night average diastolic pressure,and 24h average systolic pressure(r=0.256,0.241, 0.687,0.251,0.380,0.203,0.243,all P <0.05). Conclusion Anti -dipper blood pressure and non -dipper blood pressure have more significant damage to cardiac function and structure than dipper blood pressure in elderly patients with hypertension,and the elevation of nocturnal blood pressure is closely related to left heart structure and function damage.There is a high correlation between abnormal circadian rhythm of blood pressure and left ventricular hypertrophy in elderly hypertensive patients.