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Biomedical subjects

Y K Li

Publications and source records attributed to Y K Li.

46 records · Page 3Linked to original sources

Kinetics of transformation of aflatoxin B1 into aflatoxin M1 in lactating mouse: an ELISA analysis.

A new enzyme-linked immunosorbent assay (ELISA) was used to study the kinetics of transformation of aflatoxin B1 into aflatoxin M1 in lactating mice. Aflatoxin M1 concentration in the milk samples reached a maximum 30 min after injection of aflatoxin B1 and decreased thereafter. At the maximum time, the levels of aflatoxin M1 in the samples were proportional to the dosages administered. Aflatoxin B1 was also detected in the milk samples but at a lower concentration.

Aflatoxin B1↗

Reactivity of aflatoxin B2a antibody with aflatoxin B1-modified DNA and related metabolites.

Aflatoxin B2a (AFB2a) antiserum has been previously used in an enzyme-linked immunosorbent assay (ELISA) for the quantitation of AFB1 and AFB2a. The present investigation examined the reactivity of the antiserum toward those adducts and metabolites of AFB1 believed to play a major role in aflatoxicosis and carcinogenesis. 2,3-Dihydro-2-(N7-guanyl)-3-hydroxyaflatoxin B1 (AFB1-N7-Gua), the putative 2,3-(N5-formyl-2-2', 5',6'-triamino-4-oxo-N5-pyrimidyl)-3-hydroxyaflatoxin B1 (AFB1-FAPyr), 2,3-dihydro-2,3-dihydroxyaflatoxin B1 (AFB1-diol), AFB1-N7-Gua-modified DNA, and AFB1-FAPyr-modified DNA were prepared by in vitro incubation or chemical methods and subjected to competitive AFB2a ELISA. The antiserum showed significant reactivity with all five compounds, indicating that it had a high degree of specificity for both the cyclopentenone and the methoxy group of the parent aflatoxin molecule. Sensitivity for AFB-N7-Gua-modified DNA, AFB1-FAPyr-modified DNA, and AFB1-diol by the ELISA method was 0.1 pmol per assay. To test the applicability of immunological detection of covalent binding of AFB1 to DNA, the ELISA was compared with a conventional radioisotopic assay in two in vitro studies. The results showed that estimates of the kinetics and substrate dependence of covalent binding to calf thymus DNA in rat microsomal incubation mixtures by both methods were comparable. The broad specificity AFB2a antibody might be of considerable value in the detection of AFB1 macromolecular adducts and related metabolites in epidemiological investigations or in the diagnosis of aflatoxicosis.

Aflatoxin B1↗

Spinal manipulation in China.

BACKGROUND: Although there is a long history of the use spinal manipulation in China, little has been formally written on this topic. OBJECTIVE: To discuss the history and status of Chinese spinal manipulation. DISCUSSION: This article describes the history of Chinese spinal manipulation as revealed through past formal textbook publications on this topic, along with journal articles describing both the basic science foundation and clinical applications of such manipulation. In addition, the current status of Chinese spinal manipulation is described. CONCLUSION: There is a long history of the use of spinal manipulation throughout China, though some basic problems of application remain. Current research may help to resolve these problems.

China↗

Diagnostic value on signs of subluxation of cervical vertebrae with radiological examination.

OBJECTIVE: To investigate the relationship between radiographic signs of subluxation in the cervical vertebrae and their clinical diagnostic value. DESIGN: Controlled, clinical study. SETTING: Institute of Clinical Anatomy and Biomechanics and NanFang Hospital of the First Military Medical University, Guangzhou, China. SUBJECTS: Eighty-seven subjects with cervicodynia and 21 asymptomatic volunteers. INTERVENTIONS: Radiological signs of subluxation from anteroposterior, lateral, open-mouth and dynamic radiographs of the cervical vertebrae of the subjects were measured and analyzed. MAIN OUTCOME MEASURES: The right and left odontoid lateral mass interspace, divergence of the spinous processes, sign of double contour and position of odontoid process were studied. RESULTS: The bilateral odontoid lateral mass interspaces were asymmetrical in most cases, and the divergence of spinous processes, sign of double contour and position of odontoid process were also common. Cervical vertebrae C5, C4 and C6 showed no special variations. CONCLUSION: There was little evidence to support the contention that signs of subluxation in the cervical vertebrae are of diagnostic significance. Subluxation should be defined in two ways: as a purely roentgenological diagnosis and as a combination of roentgenological signs with clinical signs.

Adolescent↗