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Biomedical subjects

S X Li

Publications and source records attributed to S X Li.

At least 55 records · Page 3Linked to original sources
PubMed1991

Autoradiographic study of irreversible binding of [3H]beta-funaltrexamine to opioid receptors in the rat forebrain: comparison with mu and delta receptor distribution.

beta-Funaltrexamine (beta-FNA) is an irreversible mu antagonist and a reversible kappa agonist in in vivo and in vitro tests. However, whether it produces irreversible delta antagonism is controversial. In binding studies, it is clear that beta-FNA does not bind irreversibly (it does reversibly) to kappa receptors. Yet there is no consensus as to whether beta-FNA binds irreversibly to mu and/or delta receptors. In this study, irreversible binding of [3H]beta-FNA to opioid receptors was examined in rat forebrain sections in the presence of 200 mM NaCl and its distribution compared with those of mu and delta opioid receptors, labeled by [3H][D-Ala2,MePhe4,Gly-ol5]enkephalin ([3H]DAMGO) and [3H][D-Pen2,D-Pen5]enkephalin ([3H]DPDPE), respectively. Irreversible binding of [3H]beta-FNA was determined as the binding that remained following 5 washes at room temp. for 1, 5, 20, 20, and 20 min each. Non-specific binding was defined by including 10 microM naloxone, beta-chlornaltrexamine (beta-CNA), or beta-FNA in the incubation mixture. At 37 degrees C, specific irreversible binding of [3H]beta-FNA to opioid receptors reached a plateau at 10 nM in 60 min, and constituted 50-70% of total irreversible binding. Series of 4 sections of similar anatomical levels were labeled with [3H]DAMGO, [3H]beta-FNA, [3H]beta-FNA + 10 microM naloxone, beta-CNA, or beta-FNA, and [3H]DPDPE, resp., and exposed to [3H]-Ultrofilm. The distribution of [3H]beta-FNA (5 nM) irreversible labeling is very similar to that of [3H]DAMGO, i.e. patches and subcallosal streaks in caudate-putamen, patches in nucleus accumbens, dense labeling in thalamus, and more binding in the rostral than caudal striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

A survey of cigarette smoking among middle school students in 1988.

A survey of the prevalence of smoking in middle school students aged 13-21 years in Harbin city, China, was undertaken in the Spring of 1988. A random sample of 4712 students was selected using proportional stratified clustering. A self-administered confidential questionnaire relating to smoking habits and certain family and school factors was administered. The results showed that 1.29% of the students (2.21% boys and 0.38% girls) smoked regularly, 5.62% (10.52% boys and 0.76% girls) were light smokers and 13.77% (24.29% boys and 2.92% girls) smoked only occasionally. Smoking habits were related to the type of school and to age, there being a higher proportion of smoking in senior grade students. Students were significantly more likely to smoke if they were male and if their siblings smoked. Prevalence of regular smoking was not related to parental occupation or family income. It is suggested that anti-smoking education in the school curriculum should be directed towards students in middle school.

Adolescent↗
PubMed1990

Witch doctors and mental illness in mainland China: a preliminary study.

This study, the first report on witch doctors in the People's Republic of China, found that most witch doctors are poorly educated peasants who perform healing rituals as a part-time occupation. Despite being officially illegal, folk healing practices are flourishing in the countryside: 73.9% (N = 286 of 387) of psychiatric outpatients from rural areas and 70.5% (N = 43 of 61) of mentally ill persons identified in a rural community admitted to consulting witch doctors. These findings indicate an urgent need to systematically assess the beneficial and detrimental effects of these practices on China's health care system.

Adolescent↗
PubMed1990

[Treatment of septicemia after open heart surgery].

Among 404 patients who underwent open heart surgery under extracorporeal circulation, three died of septicemia. So far as we know, septicemia is one of the most serious complications after open heart surgery, and its occurrence is closely related to the duration of the operation and the extracorporeal circulation. Major prophylactic measures should include appropriate dosage of effective antibiotics in the perioperative period, strict aseptic surgical techniques during the operation, guaranteed sterilization of surgical materials and instruments, and if possible, strengthened measures of sterilization and filtration of the air in the operating room.

Adult↗
PubMed1990

Studies on kinetics of [3H]beta-funaltrexamine binding to mu opioid receptor.

beta-Funaltrexamine (beta-FNA) was shown to be a reversible kappa agonist and an irreversible mu antagonist. [3H]beta-FNA at low concentrations (less than 10 nM) covalently binds to mu but not delta or kappa opioid receptors in brain membranes. The interaction between beta-FNA and mu opioid receptors was thought to involve two steps; a reversible ligand-receptor complex is formed before the formation of an irreversible complex, based on observations in bioassays in vitro. In this study, we investigated whether such a two-step process occurred in binding using bovine striatal membranes and determined the kinetic parameters by examining the time courses of both reversible and irreversible binding of [3H]beta-FNA to mu opioid receptors. Specific binding was defined as the difference between binding in the presence of levorphanol and dextrorphan (1 microM). Reversible binding was determined as the difference between membrane (reversible and irreversible) binding and irreversible binding. At 25 degrees, the rate of formation of irreversible [3H]beta-FNA-receptor complex increased as the concentration increased and reached a plateau at 2 nM; further increase in [3H]beta-FNA concentration did not enhance the rate of formation, indicating that the rate saturation effect exists for irreversible binding of [3H]beta-FNA to mu opioid receptors. At 10 degrees and low concentrations (less than 1 nM) of [3H]beta-FNA, appreciable reversible binding to opioid receptors occurred before any irreversible [3H]beta-FNA-receptor complex could be detected. These observations support the notion that reversible binding occurs before alkylation of the receptor. The binding of [3H]beta-FNA to mu opioid receptors was thus modeled to allow for such a two-step process: (formula; see text) A mathematical analysis method was derived to allow determination of all kinetic parameters (k+1, k-1, k2, and Kd) of such a two-step reaction. Values of k2, k+1, k-1, and Kd were determined at 10 degrees for 0.5, 0.25, and 0.125 nM [3H]beta-FNA and were found to be very similar among these three concentrations. Raising the incubation temperature from 10 degrees to 37 degrees greatly enhanced the values of k+1, k-1, and k2 without affecting Kd. At 37 degrees incubation without 200 mM NaCl significantly decreased the values of k+1, k-1, and k2 without affecting Kd. NaCl increased the irreversible binding, probably by shifting the equilibrium towards a conformation that binds more easily with beta-FNA. Under all conditions examined, the value of k-1 was found to be at least 5-fold greater than k2, indicating that the majority of the reversible complex dissociates and only a small portion proceeds to form irreversible complex. This finding is consistent with published observations that only a portion of beta-FNA binding to mu opioid receptors is irreversible. In conclusion, [3H]beta-FNA binds reversibly to mu opioid receptors before forming covalent bonding...

Animals↗
PubMed1989

Surgical treatment of congenital coronary artery fistula. Report of two cases.

Two patients with congenital coronary artery fistula were treated surgically at our hospital in 1987. The fistulae originated from the left coronary artery. One patient was treated by direct ligation and the other by suture from within the left ventricle under cardiopulmonary bypass. The diagnosis and method of surgical treatment were discussed.

Adult↗
PubMed1989

[Complications of selective arteriography and arterial embolization].

Of 541 patients with selective arteriography or arterial embolization there were 16 cases developing clinically significant complications, 9(1.6%) were related to arteriography, 2 of which were pronounced hematomas at the puncture site and 7 subintimal injections in various selected arteries. 7(11.6%) complications occurred in a total of 60 cases of arterial embolization, among which there were 1 accidental embolization of the brain, 5 unexpected ischemic changes resulting in even dry gangrene and 1 vascular injury by the embolizing substance. The causes and hazards as well as prevention and management of the complications were briefly discussed.

Adolescent↗
PubMed1986

[Intracytoplasmic desmosome in squamous cancer cells of the lung in man].

Ultrastructure of intracytoplasmic (cytoplasmic) desmosomes in the squamous cancer cells of the human lung was studied by electron microscopy. In 17 cases of non-keratosic squamous cell carcinoma of the lung, intracytoplasmic (cytoplasmic) desmosomes were found in 4. In contrast to what previous investigators had proposed that the intracytoplasmic desmosomes are formed by cell fusion with the membrane being deep in the cell and cell digestion under the diffusion of hydrolytic enzymes, our result indicates that the intracytoplasmic desmosomes might be a structure formed by cell intima system itself during cell division. The structure suggests that the desmosomes originate from the cell intima system.

Carcinoma, Squamous Cell↗