Search

The aim of the present work is to observe changes in endothelium-derived factors--nitric oxide (NO) and endothelin (ET), with special reference to the regulative role of electroacupuncture (EA) in injured gastric mucosa of rat by ethanol. It was found that gastric mucosal blood flow (GMBF), transmucosal potential difference (PD) and the content of NO in the serum all decreased (P < 0.01), while the content of ET in the plasma and the lesion index (LI) of gastric mucosa increased (P < 0.01). After administration of L-Arg and SNP, the content of NO and GMBF increased significantly (P < 0.01), whereas the content of ET and LI decreased (P < 0.01). These effects were enhanced by EA at ZuSanLi (ST-36) points, which, however, were inhibited by NO biosynthetic inhibitor--L-NNA. The latter effect could be reversed by concurrent administration of L-Arg. The above results suggest that NO plays a critical part in protecting gastric mucosa against injury, which is also responsible for the protective effect of EA on injury of gastric mucosa.

Twenty-one male rabbits were administered with alum (aluminum potassium sulfate) for 32 weeks to study the accumulative toxic effects of aluminum in food additives on central nervous system. Results showed aluminum levels in blood and brain tissue of the animals increased significantly with intake of alum (P < 0.01). Blood zinc levels, and activities of superoxide dismutase (SOD) and monoamine oxidase B (MAO-B) correlated negatively with aluminum levels in blood and brain, and SOD activity correlated negatively to accumulative aluminum deposit and positively to lipid oxide level in brain. Pathological examinations showed lesions in gyrus centralis anterior, gyrus hippocampi and spinal cord of the animals got more severely and extensively with aluminum intake and brain aluminum content, with disarrangement of neurofilaments and neurotubule, and deformation of synaptic structures.

Aluminum content of 64 kinds of foods in Tianjin was determined. The results showed that the aluminum levels in different kinds of food varied greatly, and most foodstuffs from natural sources (including contamination from food processing) contained less than 10 mg/kg. Aluminum content was higher in foodstuffs of plant origin, especially dry beans contained larger amounts of aluminum naturally. It was estimated that most Tianjin inhabitants would consume 3-10 mg aluminum daily from natural sources, there being no significant difference between urban and rural inhabitants.

Mice were tested orally to study the toxic effects of Al on their skeleton and brain. The results showed that the Al content in brain increased along with its intake increase, but pathological examination of brain revealed no apparent change between test and control groups. Relative femur weight of mice in the highest dose group was lower than those of the other groups (P less than 0.05). The bone Al content was increased along with Al intake increase (P less than 0.05). There was negative correlation between the bone Al content and relative femur weight (P less than 0.05), and positive correlation between the bone Al content and the Al intake (P less than 0.01). Pathological examination of femurs revealed that the pathological changes of osteoporosis and osteoblast atrophy tended to increase while both Al intake and bone Al content were increased.

A new sesquiterpene compound named isorupestonic acid was isolated from Artemisia rupestris and its absolute stereostructure was elucidated as 3B by spectral and X-ray crystallographic methods. Interestingly, the isorupestonic acid is based upon an unusual 6, 7 membered ring skeleton differing from the 5, 7 membered ring rupestonic acid although both have the same absolute configuration at C-1. The biogenesis of isorupestonic acid most likely involves breaking the C4-C5 bond of rupestonic skeleton and forming the C5-C14 bond. The absolute configuration of rupestonic acid was also determined as 4C by X-ray analysis and CD data.

Twenty-eight condensation products of heterocycle-alpha-carboaldehydes with N-aminooxazolidones, semicarbazides, thiosemicarbazides, aminoguanidines, aromatic hydrazides and benzoxycarbonyl hydrazide were synthesized so as to deduce the antiulcer pharmacophore or fragment of furazolidone(I), the prototype, which shows therapeutic efficacy for patients with gastric ulcer. Analysis of the SAR of the compounds indicate that the substitution of furan, thiophene, pyrrole and N-methyl pyrrole rings for the 5-nitrofuran and the cleavage of the oxazolidone ring obtain the activity to some extent. The necessary electronic density of carbonyl group of compounds is of importance. A lead structure, therefore, is derived for further optimization.