Angiotensin and angiotensin converting enzyme tissue levels in two-kidney, one clip hypertensive rats

Renal tissue angiotensin I (Ang I) and II (Ang II) content and angiotensin converting enzyme activity were assessed in both kidneys during initial (7 days) and maintenance (25 days) phases of two-kidney, one clip hypertension in rats. At 7 and 25 days, systolic arterial pressure was 146 +/- 2 and 170 +/- 7 mm Hg, respectively. After 7 days, Ang I content of clipped kidneys was 64% and 70% higher (p < 0.001) than in nonclipped and sham-operated kidneys, respectively, when compared with levels in kidneys from sham-operated rats. In kidneys harvested 25 days after clipping one renal artery, Ang I and Ang II contents in clipped kidneys were increased 102% and 24% (p < 0.01), respectively. Ang II content was also 32% higher in nonclipped kidneys. Angiotensin converting enzyme activity in nonclipped kidneys was greater (p < 0.05) than that in either clipped (46% higher) or sham-operated kidneys (57% higher). Plasma Ang I and Ang II levels were elevated at 7 days but were not different at 25 days in clipped rats. These results demonstrate a dissociation between intrarenal and circulating levels of Ang I and Ang II and suggest that qualitatively different mechanisms may be responsible for the elevated intrarenal Ang II levels during the initial and maintenance phases of renal hypertension.

[Stability examination of beta-cyclodextrin inclusion compound of Zingiber officinale volatile oil]

Based on different storage time and different methods, examination has been conducted of the appearance, properties contents and main constituents in the beta-cyclodextrin inclusion compound of Zingiber officinale volatile oil. The result shows that the oil with inclusion proves considerably more stable than that without inclusion.

Dietary Na and ACE inhibition effects on renal tissue angiotensin I and II and ACE activity in rats

This study was designed to improve and validate methods for the accurate and consistent quantitation of angiotensin (ANG) I and II levels in rat kidney and to determine the effects on renal ANG I and II of changes in dietary sodium intake and ANG-converting enzyme (ACE) inhibition. Kidneys from pentobarbital-anesthetized rats were rapidly removed and homogenized in methanol before extraction and purification of ANG peptides by solid-phase extraction and high-performance liquid chromatography (HPLC). Recoveries of 125I-ANG I and II were greater than 80%. Reversed-phase HPLC of the partially purified methanol extract showed that greater than 75% of the ANG I- and greater than 82% of the ANG II-like immunoreactivity coeluted with ANG I and II, respectively. Dietary sodium deprivation (0.003 meq/g) and excess (1.34 meq/g) for 7 days significantly (P less than 0.01) increased and decreased renal ANG I (296 +/- 30 and 82.6 +/- 15.8 vs. 161 +/- 18 fmol/g) and ANG II (216 +/- 16 and 45.6 +/- 11.8 vs. 98 +/- 16 fmol/g) contents, respectively. Plasma ANG I and II levels showed similar changes. ACE activity was significantly upregulated by sodium deprivation in both kidney (44% increase) and plasma (30% increase). In rats fed normal chow, infusion of enalaprilat for 1 h abolished plasma ACE activity but decreased renal ACE activity by only 58%. ACE inhibition increased renal and plasma ANG I levels 2.8- and 12-fold, respectively, and decreased renal and plasma ANG II levels 75-78%.(ABSTRACT TRUNCATED AT 250 WORDS)

Linear response theory of ion excitation for Fourier transform mass spectrometry

A linear relation between the voltage density or magnitude spectrum of an excitation waveform and the corresponding ion orbital radius is derived for Fourier transform mass spectrometry (FTMS). This provides a theoretical foundation for the stored waveform inverse Fourier transform excitation method. The result is also useful for the design of optimal excitation signals as well as for the estimation of the kinetic energy of ions after an excitation event in collision-induced dissociation experiments. When the linear relation is applied to two-dimensional FTMS excitation, an analytical expression for ion speed modulation is obtained.

[Stability examination of the inclusion compounds of 8 Chinese medicinal volatile oils with beta-cyclodextrin]

The content, hence the stability of volatile oils and their main components in the inclusion compounds of 8 Chinese medicinal volatile oils with beta-cyclodextrin have been examined with different storage times. The 8 Chinese medicines are Vitex negundo var. heterophylla, Notopterygium incisum, Alpinia officinarum, Atractylodes lancea, Pogostenon cablin, Asarum heterotropoides var. mandshuricum, Schizonepeta tenuifolia and Amomum villosum.