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Biomedical subjects

B Li

Publications and source records attributed to B Li.

At least 631 records · Page 35Linked to original sources
PubMed1995

Mutations of the tumour suppressor gene p53 in colorectal and hepatocellular carcinomas.

The present study describes mutations of the tumour suppressor gene p53 in a local collection of colorectal and hepatocellular carcinomas (HCCs). Tumour DNA was extracted from both fresh and paraffin-embedded tissues and exons 5-8 of the p53 gene were amplified by polymerase chain reaction (PCR). Mutations were detected by single-strand conformation polymorphism (SSCP) analysis followed by direct DNA sequencing. Of the 38 colorectal carcinomas and 42 HCCs examined, 15 (39%) and 13 (31%), respectively, showed p53 mutations. Two-thirds (10/15) of the mutations in colorectal carcinomas were base transitions with a predominance at CpG dinucleotide sites--a pattern characteristic to an endogenous process in cancer development. Three mutational hotspots at codons 175, 248 and 282 were also identified. Mutations did not correlate with histological grade, Dukes stage, or metastasis. However, tumours at the distal site of the colorectum showed a higher proportion of mutations than the proximal site. In the case of HCCs, majority (9/13) of the mutations were base transitions and no mutations were observed at codon 249. This is in contrast to results from other high-incidence areas such as Africa and China, where aflatoxin is believed to be a major aetiologic factor for liver cancers. The results therefore suggest that other risk factors, rather than dietary exposure to aflatoxin, may contribute to the high HCC incidence in Singapore.

Adenocarcinoma↗
PubMed1995

[A new anti-reflux procedure: cardiac oblique invagination].

A new anti-reflux procedure, cardiac oblique invagination, was designed. Having succeeded in animal experiment, we performed this procedure clinically. Sixteen patients with sliding hiatus hernia and one with paraesophageal hernia were operated on. Reflux symptoms disappeared postoperatively. Esophageal manometric study showed that the pressure of HPZ elevated and no abnormal reflux was found by 24-hour esophageal pH monitoring. The effectiveness of this method was assumed that the abdominal segment of the esophagus, His angle, and cardiac rosette were well established and, also, this procedure fitted in with LaPlace's law. The method was simple, transabdominal, easy to teach, and it provided excellent short-term result.

Adult↗
PubMed1995

Tetrandrine, a Ca++ antagonist: effects and mechanisms of action in vascular smooth muscle cells.

Tetrandrine, an alkaloid extracted from the Chinese medicinal herb Radix stephania tetrandrae, has traditionally been used to treat hypertension. In the present study, the effect of tetrandrine on vascular smooth muscle was investigated by using the rat tail artery as a model of a resistance vessel. Tetrandrine relaxes the tension in tail artery helical strips produced by depolarization with 60 mM KCl. Further studies show that tetrandrine inhibits the KCl-induced intracellular Ca++ increase and L-type voltage-dependent Ca++ channel currents, suggesting that tetrandrine relaxes the vessel via inhibition of Ca++ influx through Ca++ channels. Tetrandrine also inhibits norepinephrine (NE)-induced vasocontraction in the presence of extracellular Ca++. It does not, however, inhibit NE-induced vasocontraction in the absence of extracellular Ca++. Tetrandrine also inhibits the NE-induced intracellular Ca++ increase in the presence of extracellular Ca++ and has no effect on the NE-induced intracellular Ca++ increase in the absence of extracellular Ca++. This suggests that tetrandrine also blocks NE-induced Ca++ influx but not NE-induced Ca++ release from the intracellular Ca++ stores. Furthermore, tetrandrine inhibits thapsigargin-induced intracellular Ca++ concentration increase, suggesting that, in addition to blocking Ca++ influx, tetrandrine also may interfere with the interaction between thapsigargin and Ca++ adenosine triphosphatase.

Alkaloids↗
PubMed1995

Serological survey of nasopharyngeal carcinoma in 21 cities of south China.

This paper reports the results of serological survey of 318,912 persons for nasopharyngeal carcinoma (NPC) in 21 cities and counties of south China. There were 8,441 persons with positive VCA-IgA antibody (single item positive) of EB virus (EBV), with a rate of 2.65%. In these VCA-IgA positive persons, 287 persons also had positive EA-IgA (double items positive) of EBV. The overall positive rate was 0.09%. 100 cases of NPC were found and 87 of them (87.0%) were in early stage. NPC found in the group with single item positive accounts for 1.19%, but the rate in the group with double items positive was 19.16% (55 cases). In NPC patients with double items positive, 49 cases were in early stage (89.1%). In 100 cases of NPC found, 45 cases appeared with negative EA-IgA, only with positive VCA-IgA, which indicated that for diagnosis of NPC, sensitivity of EA-IgA was lower than that of VCA-IgA, but its specificity was higher. Therefore, both can increase the detecting rate and early diagnosis rate of NPC. The age of people checked varied with different antibody positive rate and NPC detecting rate. The three items showed a positive correlation. The results are compatible with those of the prospective study for NPC in Wuzhou City, Guangxi, China. The method for NPC serological diagnosis can be extended and applied to raise the NPC detecting rate and early diagnosis rate at secondary prevention. And, it is further proved that there is a close relationship between NPC and EBV.

Adult↗
PubMed1995

Protective effects of nifedipine and allopurinol on high energy shock wave induced acute changes of renal function.

In a prospective randomized study, the effects of a calcium antagonist (nifedipine) and a xanthine oxidase inhibitor (allopurinal) on high energy shock wave induced impairment of renal function were examined. A total of 40 patients with renal pelvis or caliceal stones undergoing anesthesia-free extracorporeal shock wave lithotripsy (ESWL) without auxiliary measures was randomly assigned to 4 groups. Group 1 received no medication and the others received nifedipine (group 2), allopurinol (group 3) or nifedipine plus allopurinol (group 4), respectively. Nifedipine (20 mg. each) or allopurinol (0.2 gm. each) was given orally 3 times a day for a total of 4 days beginning the night before ESWL. To assess renal function the urinary excretions of beta 2-microglobulin, albumin and Tamm-Horsfall protein were determined by radioimmunoassay. After ESWL there was a significant increase in urinary beta 2-microglobulin and albumin (p < 0.001), and the urinary Tamm-Horsfall protein decreased significantly (p < 0.01) compared with before ESWL in group 1. In groups 2 and 4, however, all of the parameters after ESWL were not significantly different compared with the values before ESWL. Although the levels of urinary beta 2-microglobulin and albumin after ESWL were significantly higher (p < 0.05) than the pre-ESWL levels in group 3, the changes in urinary albumin and Tamm-Horsfall protein were milder in group 3 than in group 1. In addition, the urinary albumin level in group 2 and the urinary beta 2-microglobulin or albumin level in group 4 were less significantly different (p < 0.05) than the levels in group 1. All parameters before ESWL were not significantly different among the groups. Our results indicated that nifedipine and/or allopurinol exhibits a protective effect on high energy shock wave induced renal damage.

Adolescent↗
PubMed1995

High expression of synthetic human interferon-gamma cDNA in E. coli.

Human interferon-gamma (IFN-gamma) cDNA was synthesized, and it makes the usage of favorable codons in E. coli. The authors got 9 different expression plasmids which contain the synthetic IFN-gamma-cDNA and have different spaces between SD sequence and ATG. The free energies G0f298 in the formation of stable secondary structure in the translation initiation region (TIR) are different in various expression plasmids. One of them, pLY4-gamma 5, can highly yield INF-gamma which will be about 60%-80% of the total bacterial proteins, such a high expression was hardly noted in literature. The reasons of high expression in this work are optimal spaces between SD and ATC, favorable delta G0f298, favourable condons usage for E. coli.

Amino Acid Sequence↗
PubMed1995

[Dynamics of blood lead level in exposed workers and its effects on fetal constitutional development].

Levels of blood lead (Pb-B) and zinc protoporphyrin (ZPP) in exposed women of a storage battery plant during their early gestation and delivery stage were determined and compared with those in control women. Pb-B in exposed women kept in a consistently high level of 0.98 mumol/L and ZPP of 1.35 mumol/L. Pb-B level in umbilical cord of their neonates reached 0.90 mumol/L and ZPP 1.11 mumol/L, both of which were significantly higher than those in control women (0.26 mumol/L and 0.34 mumol/L of Pb-B and 0.51 mumol/L and 0.78 mumol/L of ZPP in women's blood and umbilical cord blood, respectively). The significance of consistent increase in Pb-B and ZPP and their effects on fetal development were discussed in the paper.

Embryonic and Fetal Development↗
PubMed1995

Superficial carcinomas of the esophagus and gastric cardia. A clinicopathological analysis of 141 cases.

From January 1970 to June 1992, 141 patients with superficial esophageal and cardiac carcinomas (SEC and SCC) underwent surgical treatment. Of the 141 patients 128(90.8%) had slight symptoms related to swallowing, and the remaining 13(9.2%) were asymptomatic. Balloon cytology and esophagoscopy proved very useful for the diagnosis of SEC and SCC, and Lugol's solution staining technique was an effective auxiliary diagnostic measure. Lymph node metastasis was not found in patients with epithelial (EP) cancer. However, it was present in one (2.9%) of 34 patients with muscularis mucosal (MM) invasion, and in 5 (8.6%) of 58 patients with submucosal (SM) cancer. The 5-year survival rates of the patients with SEC and SCC were 75.5% and 71.4%, respectively (P > 0.05). The different depth of tumor invasion including EP, MM and SM cancers showed significant differences in the 5-year survival rate (P < 0.05). Although the prognosis for the patients with lymph node metastasis is poor, we should advocate extended lymph node dissection in surgical treatment of the patients in whom MM and SM cancers are suspected.

Adenocarcinoma↗
PubMed1995

[Effects of intrasubarachnoid space injection of anti dynorphin A1-13 serum or nor-BNI on the recovery of spinal cord injury in rats].

A pronounced and reversible spinal cord compression injury was performed by the compression of a metal plate 2.2mm x 5. Omm in size to the exposed spinal dura and loaded with 35g weight for 5 minutes at T7-8. Anti dynorphin serum at 10 microliters (1:30000) or kappa antagonist nor-BNI at 100 ng was administered intrasubarachnoidly shortly after the injury, with half dose applied 1, 2, 3 h after the injury for another three times. The recovery of neurological function was investigated. The results showed that the recovery of the muscle tension and motor function of the hindlimb in anti dynorphin serum group is markedly faster than that in both control and nor-BNI groups. Also the recovery of motor function in nor-BNI group is favourable at the earlier stage of injury, comparing to the control group. There were no significant differences in the change of mean arterial pressure and blood physiological parameters among the three groups.

Animals↗
PubMed1995

[Induction of differentiation by all-trans-retinoic acid in a human lung adenocarcinoma cell line].

All-trans-retinoic acid (RA) is a powerful differentiation-inducing reagent. We examined the effect of RA on malignant phenotype of human lung adenocarcinoma cell line GLC-82 in vitro. Treatment of GLC-82 cell with 10(-5)mol/L. RA for 1-7 days resulted in suppression of cell proliferation (33-55%), inhibition of colony formation in soft agar (97.5%), and a decrease of 3H-TdR incorporation (30-60%). Cytokinetic studies demonstrated that the cells arrested in G1/G0 phase increased from 36.0% to 72.4%, which is typical for cell differentiation. Human endothelial cell transglytaminase (TGase) was expressed persistently during RA treatment. Treatment of GLC-82 cell with RA gave rise to senescence and apoptosis gradually. The results indicated that induction of differentiation and modulation of gene expression can be achieved by RA treatment in human lung adenocarcinoma cell line GLC-82.

Adenocarcinoma↗
PubMed1995

[Percutaneous ethanol injection therapy for the treatment of postoperative recurrent primary liver cancer].

This article reported 109 cases of postoperative recurrent primary liver cancer, treated with percutaneous ethanol injection therapy (PEIT) under the guidance of conventional ultrasonic transducer, the total number of injection being 637 times. No metastasis through the needle track or other serious complications were encountered. The 1.3 and 5 year survival rates were 92.6%, 47.8%, and 19%, respectively. We noted that the key factor affecting the efficacy of treatment was the accurate localization of puncture, rather than the times of injection or the quantity of ethanol injected. Criteria for the judgement of treatment and precautions to be noted concerning the procedure were suggested. It is concluded that PEIT is the treatment of choice in the management of non-operable, single, and comparativly smalle focus of postoperative recurrent primary liver cancer.

Adult↗
PubMed1995

[Preoperative embolization of paraganglioma in head and neck].

Preoperative embolization of 10 cases of paraganglioma in carotid artery body and jugular foramen region via endovascular approach was performed. Tumor vessels were obliterated 100% in 7 cases and 80% - 90% in 3 cases as was demonstrated by angiography. It is available for us to reduce bleeding, expose tumor, avoid the iatrogenic damage of the important vessels and nerves around tumor during operation and to total resection possible. Additionally, the manipulating points of embolization are discussed.

Adult↗
PubMed1995

[The establishment of ADBS data bank system for autopsy records].

The ADBS data bank system consists of PC 286 microcomputer, (or 386 and other more advanced machine) VGA color monitor, printer and ADBS V. 2.0 software. According to the international classification of diseases (ICD-9 or ICD-10, SNOMED), pathological diagnoses are coded and put into computer. This system has five functions: search, statistics, edition, print and system restore. For facilitating the operation of this system, all orders are listed as window menu. The statistic results can be shown as tables or figures and put out as disk files or prints. The system is currently an advanced computerized system of histopathological and autopsied records in Chinese.

Autopsy↗
PubMed1995

[Status and strategy of parasitosis control in preventive health care in China].

According to the result of nationwide human parasitic disease distribution survey, the public significance of parasitosis control was set forth in terms of preventive health care and economic impact as well as parasitosis control and primary health care. A suggestion was made on the control strategy aiming at the parasitosis of priorities listed in the above survey.

China↗