Pulmonary arterial hypertension (PAH) is a severe progressive disease characterized by elevated mean pulmonary arterial pressure, right ventricular hypertrophy, and eventual progression to right heart failure and death. This study aimed to examine the effect of the natural product vanillic acid (VA) on monocrotaline (MCT)-induced PAH in rats. The arginase inhibitory activity and enzyme kinetic reaction of VA were also investigated. The results showed that VA could improve pulmonary arterial pressure, pulmonary artery vascular remodeling, and right ventricular remodeling induced by MCT in rats and reduce the degree of pulmonary tissue fibrosis. Moreover, VA downregulated the gene and protein expression levels of Hif-2α, Hif-1β, and Arg2 and increased the P-eNOS/eNOS levels, thus increasing nitric oxide (NO) levels in PAH rats. Furthermore, VA was determined to be a mixed competitive arginase inhibitor with an IC50 of 26.1 μM. In conclusion, the arginase inhibitor VA exerted protective effects on MCT-induced PAH and pulmonary vascular remodeling by enhancing NO signaling pathways.

Well testing technique in the annulus of a pumping well has been a subject on which great efforts have been made by petroleum scientists and engineers in recent years. Based on the practical situation in our country this paper analyzes and discusses in detail the features of such techniques developed in our country. The paper also describes some testing devices, instruments and equipment used for the well testing in cacing-tubing annulus and puts forward their opinions as to the interpretation of the data obtained from such instruments in the downhole annulus and its application. Thus a valuable basis for the development of well testing techniques in pumping wells in our country is provided.

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