Search PubMed⌕ Search

Biomedical subjects

R Liu

Publications and source records attributed to R Liu.

At least 343 records · Page 19Linked to original sources
PubMed1992

Preclinical studies on the anticancer activity of the somatostatin analogue octreotide (SMS 201-995).

The antiproliferative effect of somatostatin-14 and its analogue, octreotide, on in vitro pancreatic and breast tumor cells has led to the suggestion that octreotide may have further oncological indications in addition to its use in the treatment of gastroentero-pancreatic (GEP) tumors. To extend these in vitro observations, we evaluated the effect of octreotide in rodent models of pancreatic and breast tumors. Octreotide at a dose of 5 micrograms or 50 micrograms twice a day in nude mice bearing solid MiaPaCa pancreatic tumors (subline 21) or ZR-75-1 breast tumors induced a significant inhibition of tumor growth from week 2 until the end of treatment at week 5. After 5 weeks, the mean volume of ZR-75-1 tumors in animals treated with the 50-micrograms regimen was 48% of that in controls. Autoradiographic studies showed that a high percentage (71%) of ZR-75-1 tumors were somatostatin receptor-positive. In addition, the growth of ZR-75-1 cells in vitro was significantly inhibited by octreotide. The drug was also tested in a second breast cancer model, 7,12-dimethylbenzanthracene (DMBA)-induced mammary tumors in rats, and continuous administration of 10 micrograms/kg/h over 6 weeks led to an approximate 50% reduction in the number of tumors arising in the rat mammary gland. These data suggest that pancreatic and breast cancer may be among the malignant diseases clinically susceptible to octreotide.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

[A new method of expanding free skin grafts].

The harvested skin was processed by a skin-cutting-machine into strips of 0.3 or 0.5 cm in width. Then, the skin strips were glued on alternate folds of a pleated sheet of paper, each fold of which was 0.3 cm or 0.5 cm in width. The paper with skin strips on it was spread flat and cut across into 0.3 cm or 0.5 cm strips. These strips were again glued to another sheet of plicate paper. After being cut across again, many small blocks of skin in equidistance were finally obtained. They were then grafted on the recipient site. The area of grafted wound was four fold or more of the original area of the harvested skin. This method has been used in 6 patients with good result.

Adhesives↗
PubMed1992

[Entrainment phenomenon of atrioventricular nodal reentrant and atrioventricular reentrant tachycardias].

Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) were induced by esophageal pacing and their entrainment zones were examined in 20 patients. The results showed that the entrainment phenomenon, which was a common electrophysiological phenomenon in reentrant tachycardia, occurred during overdrive pacing in 19 cases (19/20). The entrainment zone was 10-70 (30.50 +/- 20.85, mean +/- s) ms. The tachycardias could not be interrupted by pacing within the entrainment zone, but they were terminated by burst pacing, with starting pacing cycle length shorter than the shortest entrainment cycle length.

Adult↗
PubMed1992

[Application of serum somatomedin C level to assess the disease activity in patients with acromegaly].

Serum SMC level was measured in acromegalic patients with different disease activity. The serum SMC level of 10 untreated and 15 treated patients with active disease was 30.5 +/- 17.6 and 23.8 +/- 16.3 KU/L respectively. These levels were significantly higher than the value 2.7 +/- 2.8 KU/L in 7 patients during remitting state. The serum SMC level correlated with the basal and the nadir GH level and the area under the GH curve in glucose suppression test. The serum SMC levels in 6 patients with prolactinoma, 10 patients with Grave's disease and 8 patients with renal failure were all in normal range, but in 10 patients with liver cirrhosis it was 0.36 +/- 0.39 KU/L, which was significantly lower than the normal value. We concluded that serum SMC level is a good criterion for assessment of disease activity of acromegaly for it does not require a dynamic test and it does not increase in other diseases.

Acromegaly↗
PubMed1992

[The incidence of low birth weight infant in north China].

From September 1989 to August 1990, the incidence of low birth weight (LBW) infant was studied collaboratively in 8 areas in north China. 29,941 infants (14,003 males and 12,938 females) were investigated, 1,348 LBW infants included those of preterm and small for gestational age (SGA) term. The incidence of LBW infant was 5.00%. The incidence of male preterm (3.15%) was higher than that of female preterm (2.39%). The incidence of female SGA term (2.46%) was higher than that of male SGA term (1.82%). 52.09% of the infants with birth weight (BW) < 2,500g was of SGA term. 35-36 weeks premature infants accounted for 61.78% and 1,500-2,499g LBW infants for 93.28%. The incidence of SGA preterm (GA < 37 weeks) was 17.8%. In this study, the incidence of LBW infant was higher in Changchun and Huhehot than in other areas.

China↗
PubMed1992

Effects of Chinese herbal drugs on serum lipids, lipoproteins and apolipoproteins in mild to moderate essential hypertensive patients.

We investigated the effects of the traditional Chinese herbal drugs, Dai-saiko-to (D) and Saiko-ka-ryukotsuboreito (S) on blood pressure, pulse rates, serum lipids, lipoproteins and apolipoproteins in 30 patients with mild to moderate hypertension in an open, randomised trial. After the drug treatment, BP remained unchanged, but pulse rates declined significantly after 3 months in the S treated group. Serum total cholesterol and triglyceride values did not change, but high density lipoprotein-cholesterol increased significantly (P < 0.05) in both groups. Apo-AI (P < 0.1 in S group) and apo-AII (P < 0.05 in D group, P < 0.1 in S group) tended to increase 3 months after treatment. These data indicate that both of these traditional Chinese medicines have a preferential effect on lipid metabolism with little antihypertensive action.

Apolipoproteins↗
PubMed1992

Prevalence of growth hormone deficiency of children in Beijing.

103,753 (male 51,994, female 51,759) primary and middle school students aged 6-15 years in two districts in Beijing city were surveyed from October 1987 to April 1989. The heights of the students were measured. According to the height standard of northern cities in China, 202 students with heights below the 3rd percentile for age were requested for detailed history, physical examination, screening GH test bone age, T4, SGPT, chest X-ray, routine urine test and sex chromatin (in female). If GH less than 10 micrograms/L, two provocative tests (L-dopa or clonidine and insulin hypoglycaemia test) were done. Then the heights of the short students were observed for 1/2-2 years. GHD was diagnosed in 12 cases based on the GH peak levels less than 10 micrograms/L in two provocative tests, whose growth velocity was slower than that for students of the same age and sex. Of these subjects with GHD, total GHD (GH less than 5 micrograms/L) was present in 7 and partial GHD (GH = 5-9.9 micrograms/L) in 5. The 12 GHD students (male 9, female 3) aged 8.9-15.7 years accounted for 1/8,646 in the total surveyed students. The male and female GHD accounted for 1/5,777 and 1/17,253 in the total males and females respectively.

Adolescent↗
PubMed1992

[The characterization of mutant No. 68 from midecamycin producing strain S. mycarofaciens 1748].

A stable mutant No. 68 was obtained by treatment of S. mycarofaciens 1748 spores at high temperature. The electromicroscopic examination has shown that the mutant No. 68 and parent strain 1748 both have the spore chains of the spiratype. The spores of both strain are cylindrical in shape. The only difference is that the spores of the mutant No. 68 are of smooth surface, but the 1748 are of thorny. The physiological characteristics of both strains are also very similar with slight differences in utilization of few carbon sources and in cultural characters in few medium. Feeding experiment has shown that the mutant No. 68 was blocked in the formation of the macrolide lactone in the midecamycin biosynthetic pathway. This suggested that the mutant No. 68 might be a polyketide synthase genes deficient mutant. The ability of the mutant No. 68 to convert spiramycin into 4"-propionylspiramycin indicated that the mutant No. 68 contained the midecamycin 4"-propionyltransferase and could be used for microbial bioconversion of spiramycin into 4"-propionylspiramycin.

Leucomycins↗
PubMed1991

In vitro cytotoxicity against fresh human tumors and P388 leukemia predicts the differential in vivo activity of a series of anthracene anticancer drugs.

To date, random anticancer drug screening has proven to be relatively inefficient and non-specific with respect to selecting active compounds for most tumor types (except for leukemia/lymphoma). Although large numbers of compounds from diverse sources were evaluated for many years in the P388 mouse leukemia model, only a few clinically useful drugs have been identified by this in vivo screening method. Thus, there is intense interest in the development of more effective in vitro screening models for new anticancer drugs. In the present paper we have compared the discriminating power for fresh human tumors from patients, human tumor cell lines developed from 11 patients and murine P388 leukemia in tumor colony forming assays as indicators of cytotoxicity for a series of anthracene antitumor agents. Two of a series of 21 novel bisantrene analogs, R6 (N,N1-bis[2-(dimethylamino)ethyl]-9,10-anthracene-bis(methylamine)) and R26 (N,N1-bis(1-ethyl-3-piperidinyl)-9,10-anthracene-bis(methylamine] produced significant cytotoxicity against the 11 human tumor cell lines and were therefore selected for additional in vitro and in vivo studies. R26 was specifically selected for further testing since it had similar in vitro potency as mitoxantrone, but showed no cross-resistance against mitoxantrone-resistant WiDr colon or doxorubicin-resistant 8226 myeloma cell lines. In contrast to the cell line data, only of the 22 fresh human tumors showed significant in vitro sensitivity (i.e. less than 50% survival of tumor colony forming units) to either R6 or R26 tested at high concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Organic anion transport in HepG2 cells: absence of the high-affinity, chloride-dependent transporter.

In previous studies, we identified a 55 kD organic anion-binding protein in liver cell sinusoidal plasma membrane subfractions. Other investigators identified another 55 kD bromosulfophthalein/bilirubin binding protein on the surface of rat hepatocytes and HepG2 cells and suggested that this protein served as a transporter for these ligands. In this study, transport of 35S-sulfobromophthalein by the human hepatoma cell line, HepG2, was quantified in the presence and absence of bovine serum albumin to further clarify the possible function of these plasma membrane binding proteins. In contrast to results in normal rat hepatocytes, virtually no uptake of 35S-sulfobromophthalein by HepG2 cells in the presence of bovine serum albumin was found. In the absence of albumin, HepG2 cells expressed temperature-dependent uptake of 35S-sulfobromophthalein. However, the high-affinity Cl(-)-dependent sulfobromophthalein transport that characterizes normal rat hepatocytes was absent, as indicated by an approximately 95-fold lower affinity and 170-fold higher capacity of HepG2 cells for sulfobromophthalein compared with previous results with rat hepatocytes. These results suggest that 55 kD sulfobromophthalein/bilirubin-binding protein on the liver cell surface differs from organic anion-binding protein and is not responsible for sulfobromophthalein extraction in the presence of albumin, although it may play some role in lower affinity transport by cells. Immunoblot analysis and metabolic labeling of HepG2 cells demonstrated synthesis of organic anion-binding protein. However, light microscopic immunocytochemistry and immunoprecipitation of surface iodinated rat hepatocytes and HepG2 cells with antibody to a recombinant organic anion-binding protein fusion protein indicated absence of organic anion-binding protein on the surface of HepG2 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Modification of the clonogenic assay for the detection of lymphokine activated killer cell activity.

The soft agar clonogenic assay using [3H]thymidine uptake as an endpoint was adapted for the detection of human LAK activity against the Daudi lymphoma cell line and human tumor cells obtained by biopsy. Using Daudi cells as the target population the modified agar assay was more sensitive than the conventional 4 h 51Cr release assay. Use of a single layer agar assay allowed the assessment of LAK cytotoxic/cytostatic activity against Daudi lymphoma cells after cell to cell contact, while a two layer system permitted evaluation of the role of soluble mediators in LAK/target cell interactions. This study shows that LAK cells can either kill or inhibit the proliferation of Daudi cells by two mechanisms: one which requires cell-to-cell contact, and a second via soluble mediators. As determined by the use of neutralizing antisera, the soluble factor(s) are not tumor necrosis factor and interferon-gamma. Of the nine individual human tumor samples obtained by biopsy. 89% were sensitive to allogeneic LAK cells when the two populations were admixed. Of these nine tumors 44% were inhibited by LAK-derived soluble factors. The soft agar assay system should serve as a useful tool for determining the sensitivity of human tumors to LAK cells and for studying the mechanisms of LAK anti-tumor activity.

Colony-Forming Units Assay↗