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Biomedical subjects

B S Li

Publications and source records attributed to B S Li.

45 records · Page 3Linked to original sources
PubMed1989

[Synthesis and antimalarial and antineoplastic activities of some derivatives of 2,4-diamino-5-methyl-6-substituted benzylaminoquinazolines].

This paper reports the synthesis and the antimalarial and anticancer activities of some derivatives of 2,4-diamino-5-methyl-6-substituted benzylaminoquinazolines. These compounds were synthesized by condensation of 5-methyl-2,4,6-triaminoquinazoline with substituted benzyaldehyde to produce Schiff base, followed by reduction, formylation or nitrosation. The suppressive therapeutic effects against Plasmodium berghei in mice showed that the suppressive rate of three compounds (IV 2,5,6)was 100 per cent at the dosage 5 mg/kg. The anticancer activity in vitro showed that II7 and IV3 had the strongest inhibition and their IC50 against L1210 Leukemia cell were 3.910 X 10(-3) micrograms/ml and 6.172 X 10(-3) micrograms/ml.

Aminoquinolines↗
PubMed1989

[Synthesis and antimalarial as well as antitumor activities of 1-methyl-2,4-diamino-6-(N-methyl-substituted benzylamion) quinazolinium iodides].

Fourteen 1-methyl-2,4-diamino-6-(N-methyl-substituted benzylamino) quinazolinium iodides (II) were synthesized by treatment of 2,4-diamino-6-substituted benzylaminoquinazolines with methyl iodide. Three compounds (II4,7,10) were shown to produce 100% suppression on Plasmodium berghei in mice at oral dose of 20 mg/kg and II4 was found to inhibit twice as much as methotrexate on L1210 Leukemia cells in culture.

Animals↗
PubMed1987

Iron deficiency and hearing loss. Experimental study in growing rats.

Cochlear changes were studied in 141 growing rats raised on a basic iron-deficient diet for 7-100 days; 130 rats served as normal or chronic anemia controls. Electrophysiological findings showed that the incidence of an auditory threshold elevation of more than 15 dB was 31.85% in the iron-deficient rats, but it was unchanged in all the control animals. The main cochlear histopathological changes induced by iron deficiency were strial atrophy and reduction of spiral ganglion cells. It is concluded that the observed anomalies may be attributed solely to iron deficiency of the cochlear tissue.

Animals↗
PubMed1986

The role of Phlebotomus alexandri Sinton, 1928 in the transmission of kala-azar.

Since 1968, kala-azar has been occurring sporadically in Meiyaogou, Turfan County, Xinjiang-Uygur Autonomous Region, where four species of sandflies are known to exist. The present study of sandflies collected in this area from May to August 1983 shows that Phlebotomus alexandri is the only anthropophilic and predominant species, accounting for 81.1% (7716/8843) of the sandfly population. After having been fed on cotton rats or hamsters infected with Leishmania donovani, 93.9% (230/245) of P. alexandri were infected, the promastigotes not only developing in the stomach but also invading the pharynx, buccal cavity and proboscis. Of the 643 female P. alexandri collected in the wild and in house, 13 (2.0%) were found to be naturally infected, with a distribution of promastigotes similar to that in the experimental infection. All the Chinese hamsters and golden hamsters that had been inoculated with 7 isolates of promastigotes from naturally infected sandflies developed visceral leishmaniasis. In addition, golden hamsters could be infected experimentally by the bite of P. alexandri which had an infection of promastigotes of L. donovani. This is the first demonstration of a species of Paraphlebotomus playing a role in the transmission of kala-azar in the Old World; studies for confirmation by biochemical identification of parasite isolates from naturally infected P. alexandri are now in progress.

Animals↗
PubMedDate not supplied

A scanning electron microscopic study of cochlear changes in iron-deficient rats.

The effects of iron deficiency on the cochlea were studied in growing rats fed with a basic iron-deficient diet for 80 days. The electrophysiological changes (auditory thresholds raised more than 15 dB) were observed in 47% of the cochleas of iron-deficient rats. When these organs of Corti were examined by scanning electron microscopy, abnormalities of outer or inner hair cells were found, as follows: (1) fusion and torsion of the stereocilia, (2) coalescence of adjacent stereocilia in the same row, (3) loss of sensory hair stiffness, and (4) loss of stereocilia. Within each lesion, the neighbouring supporting cells and their microvilli showed no damage. The findings indicate that cochlear impairment can be induced by iron deficiency. The peroxidative mechanisms responsible for the lesions of stereocilia in iron deficiency are discussed.

Anemia, Hypochromic↗