Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China.

OBJECTIVE: To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. METHODS: A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). FINDINGS: After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. CONCLUSION: The slightly higher dose of vaccine did not seem to alter efficacy significantly in China.

Synthesis, characterization, and antibacterial activity of novel Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes with vitamin K3-thiosemicarbazone.

Vitamin K3-thiosemicarbazone (C12H11N3NaO4S2 x 5H2O, abbreviated as VT), a new Schiff base derivative, has been synthesized. Its crystal structure, determined by X-ray diffraction, is triclinic, space group P1. We have also prepared five novel complexes of VT with transition metals: [M(VT)(2)2H2O] x nH2O, (n = 1 and 2 for M = Cu(II) and Zn(II), respectively) and [M'(HVT)2Cl2] x mH2O, (m = 4, 5, and 7 for M' = Co(II), Mn(II), and Ni(II), respectively). These compounds were characterized by IR and UV-Vis spectroscopy, molar conductivity, thermal analyses, complexometric titration, and elemental analysis. In all the complexes, the VT ligand coordinates through sulfur and oxygen atoms, and the geometry around metal atom is best described as octahedral. In vitro tests of antibacterial activity showed that VT and its complexes with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) all had strong inhibitory actions against G(+) Staphylococcus aureus, G(+) Hay bacillus, and G(-) Escherichia coli.

Doppler color flow mapping of the proximal isovelocity surface area: a new method for measuring volume flow rate across a narrowed orifice.

This manuscript describes a new method, validated in in vitro models, for quantitating volume flow rate across an orifice with Doppler color flow mapping. Flow through a narrowed orifice is characterized by the convergence of radial streamlines proximal to the orifice. In this color Doppler method, one or more isovelocity surface areas (PISA), delineated by blue and red aliasing velocity interfaces, can be identified proximal to the narrowed orifice. Volume flow rate (in milliliters per second) can then be calculated as PISA (in square centimeters) multiplied by the isovelocity of the PISA (in centimeters per second). Doppler color flow mapping was performed in in vitro models of constant and pulsatile flow through an orifice in a wall. The first proximal isovelocity surface area, with an isovelocity corresponding to the aliasing velocity, that is, one half the Nyquist sampling limit, could be identified as a blue and red color interface proximal to the orifice. Over a range of circular orifice diameters from 3 mm to 16 mm and flow rates from 0.5 to 18.7 L/min, the proximal isovelocity surface area could be imaged in two planes. This PISA was best described by a hemielliptic mathematical model with two different radii measured from long-axis and short-axis views. In the constant flow model, volume flow rate calculated from the Doppler PISA correlated well with actual volume flow rate measured simultaneously with a cylinder and stopwatch (r = 0.98, p less than 0.001, standard error of the estimate [SEE] = 0.36 L/min). In the pulsatile flow model, with jet velocities ranging from 2.6 to 7.7 m/sec and flow volume ranging from 1.0 to 10.3 L/min, calculated volume flow rate also demonstrated an excellent correlation with actual volume flow rate (r = 0.99, p less than 0.001, SEE = 0.53 L/min). Findings from these in vitro models suggest that quantification of the proximal isovelocity surface area by Doppler color flow mapping appears to be a promising technique for estimating volume flow rate across a narrowed orifice. This new color Doppler flow method may have advantages over previous Doppler methods in estimating volume flow rate in various clinical situations, for example, valvular regurgitation and shunt lesions.