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Biomedical subjects

F S Li

Publications and source records attributed to F S Li.

17 recordsLinked to original sources

Isolation and complete nucleotide sequence of a Chinese Sindbis-like virus.

Infection with alphaviruses is common in the Chinese population. Here we report the isolation of a Sindbis-like virus from a pool of Anopheles mosquitoes collected in Xinjiang, China during an arbovirus survey. This virus, designated XJ-160, rapidly produced cytopathic effects on mosquito and hamster cells. In addition, it was lethal to neonatal mice if inoculated intracerebrally. Serologically, XJ-160 reacted with and was neutralized by an anti-Sindbis antibody. Anti-XJ-160 antibodies were found in several cohorts of Chinese subjects. The complete 11626-base nucleotide sequence of XJ-160 was determined. XJ-160 has diverged significantly from the prototype Sindbis virus, with an 18% difference in nucleotide sequence and an 8.6% difference in amino acids; there are 11 deletions and 2 insertions, involving 99 nucleotides in total. XJ-160 is most closely linked to Kyzylagach virus isolated in Azerbaijan. Both belong to the African/European genetic lineage of Sindbis virus, albeit more distantly related to other members.

Alphavirus Infections↗

[Simultaneous determination of sulbactam sodium and cefoperazone sodium in sulperazon by high performance liquid chromatography].

A reversed-phase, isocratic high performance liquid chromatographic method with acid mobile phase can separate sulbactam and cafoperazone within 12 minutes. Column packed with Hypersil ODS2(250 mm x 4.6 mm i.d., 5 microns) was manufactured by Dalian Elite Company. Mobile phase is composed of water (adjusted to pH 4.0 with 1% phosphoric acid) and acetonitrile (80:20, V/V). The detection was performed at 210 nm and the injection volume was 2 microL. Cefoperazone and sulbactam have good linearity in the ranges of 100 mg/L to 800 mg/L and 100 mg/L to 1,000 mg/L with the correlation coefficients of 0.9991 and 0.9997 respectively. This method is easily to be operated and can be applied for manufacturing and medicinal study.

Anti-Infective Agents, Urinary↗

Changes in the concentrations of trace elements in human milk during lactation.

Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine 18 trace elements (Ba, Be, Bi, Cd, Co, Cs, Cu, La, Li, Mn, Mo, Pb, Rb, Sb, Sn, Sr, Tl, and Zn) in 55 human milk samples from 46 healthy mothers collected during lactation periods extending to 293 days after birth. Se was quantified by hydride generation atomic absorption spectrometry (HG-AAS). To test the accuracy and the precision of the analytical procedure, milk powder reference materials (BCR 063 and BCR 150) were analyzed. The results obtained by ICP-MS and HG-AAS showed good agreement with the certified values. Whenever available, trace element concentrations determined in the human milk samples were compared to reliable literature data. The concentrations of Be (< 0.05 to 0.9 microgram/kg), Bi (< 0.09 to 2.0 micrograms/kg), Cs (1.7 to 7.7 micrograms/kg), La (< 0.05 to 3.7 micrograms/kg), Rb (440 to 1,620 micrograms/kg), and Tl (< 0.08 to 0.5 microgram/kg) are the first to be reported for human milk. The concentrations of the essential trace elements Cu (p < 0.005), Mn (p < 0.05), Mo (p < 0.0005), Se (p < 0.001), and Zn (p < 0.0005) significantly decreased and the concentrations of cobalt significantly increased (p < 0.005) in human milk during the course of lactation. All concentrations for the essential trace element tin in the human milk samples were below the method detection limit of 0.3 microgram/kg. Among the not essential and toxic elements-with the exception of Ba, Pb, and Tl-the trend toward lower concentrations with continuing lactation is much less pronounced than for the essential trace elements. With the exception of Se, the daily intakes of essential trace elements of fully breast-fed infants are considerably lower than dietary recommendations.

Female↗

Presenile (early ageing) changes in tissues of Kaschin-Beck disease and its pathogenetic significance.

The selenium level and activity of glutathione peroxidase in blood of children living in Kaschin-Beck disease (KBD) endemic areas were lower than that in nonendemic areas. KBD children were deficient in selenium, their lipid components, structure and function of the red cell membrane and cartilage tissue were abnormal. That is, the phospholipid (PL) content in the tissues of the patient was less than that of the controls in endemic and non-endemic areas. Especially as the phosphatidylcholine (PC) content decreased significantly, but sphingomyelin (SM) increased, the molar ratio of SM/PC and cholesterol (Ch)/PL increased. Increase of acanthocyte content was seen under the electron microscope and the fragility of erythrocytes was also increased. It indicated that there were membrane defects and membrane damage in KBD. At the same time, the sulfation extent of mucopolysaccharides in cartilage of patients was lower, and the collagen content was higher than that of controls. The presenile changes in lipid composition, structure and function of biomembranes and cartilage metabolism of KBD are very significant in studies on the aetiological pathogenesis of KBD and other ageing diseases.

Aging↗

Recombinant bivalent live vaccines against neonatal colibacillosis in piglets.

The genes of colonization factor K88 and avirulent heat-labile enterotoxin LT A-B+ of enterotoxigenic E. coli (ETEC) have been ligated, and a vaccine strain containing recombinant plasmid that efficiently expresses two antigens has been obtained. Using the activity of beta-galactosidase as a selection marker instead of drug resistance, another bivalent vaccine strain with the same expression level has also been constructed. The vaccine strains have no toxicity and do not cause any adverse reactions. In challenge study and field trials, a high degree of protection from colibacillosis was afforded to piglets when their dams were immunized orally or parenterally. Practice of bivalent live vaccines including colonization factor and enterotoxin antigens and without antibiotic resistance gene shows effective.

Adhesins, Escherichia coli↗

[Effect of thoracentesis on arterial blood gas tension].

The effect of thoracentesis on arterial blood gas tension was studied in 30 patients with unilateral free pleural effusions of various causes. Arterial blood gases were measured before thoracentesis and at 20 minutes, two hours after the procedure. P(A-a)O2 was determined at the same time. The PaO2, PaCO2 and HCO3 showed significant decrease but the concurrent significant increase of the P(A-a)O2 before thoracentesis. The PaO2 showed increase and P(A-a)O2 decrease but the PaCO2 not changes after thoracentesis 20 minutes and two hours. The results suggested that pleural effusion might result in hypoxaemia and chronic compensated alkalosis.

Adolescent↗

The construction of a non-antibiotic resistant ETEC vaccine strain containing K88ac and LT-B antigens.

By inserting the LacZ gene into the plasmid containing ETEC LT-B antigen gene we obtained a recombinant plasmid which could express the beta-galactosidase and LT-B antigen, but has the Tc resistant gene. The K88ac antigen gene was then inserted into the BamHI site of the Tc resistant region in the above plasmid. The final recombinant plasmid has no antibiotic resistance gene but can stably express both LT-B and K88ac antigens, as well as the beta-galactosidase as a tracking marker.

Antigens, Bacterial↗

[Study of oxidative damage on mitochondrial membrane of myocardium deficient in selenium].

Keshan disease (KD) is an endemic cardiomyopathy with membrane damage of the myocardial mitochondria. This paper reports the results of feeding guinea pigs with a forage obtained from KD endemic area. The selenium (Se) content and glutathione peroxidase activity in blood, tissues, mitochondria, microsome and supernatant of myocardium and liver cells of the experimental group were decreased. Additionally, the activity of glutathione-S-transferase was also decreased to some extent, instead of being increased in normal cases, and the content of lipid peroxide and hydroperoxide was increased. At the same time, cardiolipin in mitochondria, and the activity of cytochrome C oxidase (CCO, an enzyme binding with mitochondrial membrane) were also reduced accompanied with oxidative damage and disorder of function of the membrane. Anyhow, when exogenous cardiolipin was added in the purified endemic CCO solution, it was capable of restoring CCO activity significantly. The significance of Se deficiency and unbalanced diet in pathogenesis of Keshan disease is discussed.

Animals↗

Etiologic and serologic investigations of the 1980 epidemic of dengue fever on Hainan Island, China.

Virologic and seroepidemiologic studies were carried out during an epidemic of dengue fever on Hainan Island in 1980. Dengue 3 virus was isolated from 46 of 77 acute phase sera and from 1 of 10 pools of adult Aedes aegypti. Dengue 1 virus virus was isolated from a single acute phase serum. Seroepidemiologic investigations showed that 74% of healthy individuals in the epidemic area had antibody to dengue virus compared to 54% in an area where epidemic dengue had occurred in 1978, and less than or equal to 8% in nonepidemic areas. There were no significant differences in antibody prevalence for different sex and age groups.

Aedes↗