Biomedical subjects
Publications and source records attributed to W Song.
This paper deals with the determination of the lignins in 10 species of Schisandra crude drugs by TLC-densitometry. The result shows that all the 10 species are unidentical in the lignin constituents; the same species vary in the contents with habitats; and the TLC chromatograms of the 10 species differ distinctly from each other.
Because both chemical and mechanical insults to the lung may occur concomitantly with trauma, we hypothesized that the pressure threshold for vascular pressure-induced (mechanical) injury would be decreased after a chemical insult to the lung. Normal isolated canine lung lobes (N, n = 14) and those injured with either airway acid instillation (AAI, n = 18) or intravascular oleic acid (OA, n = 25) were exposed to short (5-min) periods of elevated venous pressure (HiPv) ranging from 19 to 130 cmH2O. Before the HiPv stress, the capillary filtration coefficient (Kf,c) was 0.12 +/- 0.01, 0.27 +/- 0.03, and 0.31 +/- 0.02 ml.min-1.cmH2O-1 x 100 g-1 and the isogravimetric capillary pressure (Pc,i) was 9.2 +/- 0.3, 6.8 +/- 0.5, and 6.5 +/- 0.3 cmH2O in N, AAI, and OA lungs, respectively. However, the pattern of response to HiPv was similar in all groups: Kf,c was no different from the pre-HiPv value when the peak venous pressure (Pv) remained less than 55 cmH2O, but it increased reversibly when peak Pv exceeded 55 cmH2O (P less than 0.05). The reflection coefficient (sigma) for total proteins measured after pressure exposure averaged 0.60 +/- 0.03, 0.32 +/- 0.04, and 0.37 +/- 0.09 for N, AAI, and OA lobes respectively. However, in contrast to the result expected if pore stretching had occurred at high pressure, in all groups the sigma measured during the HiPv stress when Pv exceeded 55 cmH2O was significantly larger than that measured during the recovery period.(ABSTRACT TRUNCATED AT 250 WORDS)
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Nine new compounds were synthesized and tested for their alpha-adrenoceptor affinity and antihypertensive activity together with 5 other previously reported compounds. Compounds I, IIa, IIb and IIIa showed high alpha-adrenoceptor affinity and strong antihypertensive activity.
Both noradrenaline administration to rats and rapid cardiac pacing in dogs induces delayed protection of the heart against ischaemia-induced ventricular arrhythmias. In an attempt to establish molecular mechanisms underlying the delayed cardioprotection, we have examined the potential role of two kinases, PKC epsilon and p42/44MAPK. These protein kinases are expressed in the ventricles of the heart and are characterised by their ability to regulate ion-flux and gene transcription. In the rat p42MAPK is predominantly localised in the high-speed supernatant fraction of the ventricle homogenate, whereas p44MAPK is enriched in the nuclear low speed pellet. A small proportion of the p42MAPK is activated even in hearts from control animals. However, neither kinase is relocalised or activated by noradrenaline administration and this provides preliminary evidence the p42/44MAPK may not play a significant role in delayed protection in this species. In contrast, noradrenaline does induce the translocation of PKC epsilon to cell membranes, a response that is sustained for up to 4 h. However, PKC epsilon is down-regulated from the cytoplasm after 24 h post noradrenaline treatment. PKC epsilon is also translocated to the membrane in dogs that have been classically pre-conditioned and cardiac paced. In the latter case, translocation of PKC epsilon from the cytoplasm to the cell membrane is evident 24 h after pacing. These results indicate that the release of endogenous mediators may either inhibit down-regulation or elicit an increase in PKC epsilon mRNA expression. Therefore, in dog heart the subcellular relocalisation of PKC epsilon persists into the 'second window' and may play a central role in the molecular mechanism governing delayed cardioprotection. It is important in the future to identify either the gene products that are induced or the target protein(s) that are phosphorylated by PKC epsilon.
It has been proposed that taurine, or one of its metabolites, may exert anti-arrhythmic effects in cardiac muscle. The present studies examined the effects of acute left ventricular ischemia in the dog (in vivo) and whole heart anoxia in the perfused rat heart (in vitro) on the content and distribution of taurine. In control dogs an increasing outer-to-inner gradient in taurine content was observed in the left ventricle. Left circumflex artery ligation for four hours markedly decreased tissue taurine content, the greatest disappearance occurring in the inner zone. Anoxic perfusion resulted in a similar decrease in rat ventricular taurine levels. Recovery of taurine in the heart perfusates indicated that tissue disappearance, secondary to oxygen deficiency, involved leakage into the extracellular fluid rather than metabolic conversion.
In order to study the effects of isovolumic hemodilution and its combination with Danshen solution on acute ischemic reperfused canine myocardium, 24 adult hybrid dogs were used and divided into four groups. Group I was the control group, groups II-IV were treated with Dextron 40, Danshen solution and a combination of the two, respectively. The results showed that either Dextron 40 or Danshen solution alone had a significant increase of +/- dp/dt-max when compared with group I (p < 0.05). Although no significant difference existed between group II and III, the former showed more rapid action. The combination of the two therapies improved +/- dp/dt-max and LVSP, and significantly reduced the necrotic sizes and the MDA contents in the ischemic myocardia compared with not only group I, but also group II or group III (all p < 0.05). The results suggest that isovolumic hemodilution or Danshen may protect the ischemic reperfused myocardium and the former may come into action more rapidly, and that the combination of the two may show a better synergism than each one of the two by itself.