[Studies on chemical constituents of Smilax menispermoidea D.C].
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Diosgenin↗
Biomedical subjects
M Du
Publications and source records attributed to M Du.
[Free radical scavenging and antifatigue activities of Saussurea involucrata polysaccharides].
The polysaccharides of Saussurea involucrata Kar et Kir was first isolated and identified by us. The polysaccharides scavenged superoxide anions by nitroblue tetraazolium colorimetric method with a median scavenging concentration of 22 micrograms.ml-1 and 95% confidence limit was 19.9-24.1 micrograms.ml-1. The polysaccharides inhibited the formation of thiobarbituric acid reaction substance in mouse liver homogenate and its IC50 was 2.3 mg/g fresh liver and 95% confidence limit was 2.05-2.55 mg/g fresh liver. By ip 25 mg.kg-1.d-1 x d in mice, the polysaccharides decreased oxygen consumption by 34.4% and ip same dosage x 6 d, the polysaccharide prolonged swimming time by 1.69-fold.
Animals↗
[Studies on the early development of nucleocytoplasmic hybrid embryos between mouse and rabbit by nuclear transplantation].
Nuclear transplantation has been proved to be a very powerful method in researching the relationship between nucleus and cytoplasm during embryogenesis. Electrofusion is a new means of cell fusion which is being improved in the past nearly ten years. In this study, we produced interorder nucleocytoplasmic hybrid embryos between mouse and rabbit with these two techniques. Two phenomena, i.e. premature chromosome condensation (PCC) and nuclear swelling, were observed after mouse 8-cell stage blastomeres were fused into rabbit enucleated oocytes. After 4.5-days cultured in mouse oviducts, 5.4% reconstituted embryos developed into blastocysts. By karyotype examination, it was known that only mouse chromosomes were presented in the blastomeres, one blastocyst even had a normal mouse karyotype (2 n = 40, XX). As a conclusion, we consider it is possible to obtain normal early development of interspecies nucleocytoplasmic hybrid embryos between mouse and rabbit.
Animals↗
[Production of transgenic rabbits by micro injection].
The feasibility of using whole animal instead of bioreactor in genetic engineering has been investigated with transgenic domestic rabbits. The gene chosen is the surface gene (S gene) of hepatitis B virus. Two plasmids were specifically constructed for this purpose, pHBV3.0 contains the promoter pre S gene and a part of c gene of the virus; while MT-SA, the S gene and mouse MT promotor. These plasmids were made linear by suitable restriction endonuclease before they were transferred into maleprounclei by means of microinjection. From 757 microinjected and transplanted fertilized eggs 101 rabbits were obtained. 57% of these animals were found with integrated microinjected genes. 28 of the transgenic animals were tested for the presence of the surface antigen of the virus in the serum by ELISA method. 8 animals were found positive, approximately 30% of the tested transgenic animals. The second generation transgenics were obtained either by first generation ransgenics crossed with non-trans-genics or transgenics. Among them 73% contained the transgene and 15% had the surface antigen in the serum. Some experiments were also carried out with human growth hormone gene.
Animals↗
Femtosecond spontaneous-emission studies of reaction centers from photosynthetic bacteria.
Spontaneous emission from reaction centers of photosynthetic bacteria has been recorded with a time resolution of 50 fs. Excitation was made directly into both the special-pair band (850 nm) and the Qx band of bacteriochlorophylls (608 nm). Rhodobacter sphaeroides R26, Rhodobacter capsulatus wild type, and four mutants of Rb. capsulatus were studied. In all cases the fluorescence decay was not single exponential and was well fit as a sum of two exponential decay components. The short components are in excellent agreement with the single component detected by measurements of stimulated emission. The origin of the nonexponential decay is discussed in terms of heterogeneity, the kinetic scheme, and the possibility of slow vibrational relaxation.
Energy Transfer↗
Clinical trial on termination of early pregnancy with RU486 in combination with prostaglandin.
Termination of early pregnancy was performed in 1572 healthy women with RU486 (mifepristone, 600mg orally once), followed 36-60 hours later by administration of methyl ester of dl-15-methyl-PGF2 alpha (PG05, 1mg vaginal suppository). Complete abortion was accomplished in 91.2% (1433/1571), incomplete abortion in 4.8% (76/1571), and continued pregnancy in 3.9% (62/1571). The time elapsed between RU486 intake and complete expulsion was 2.4 +/- 1.3 days. Expulsion took place on the third day in 935 women (72%), and on the 4th day in 273 women (21.0%). Uterine bleeding occurred on the second or third day after RU486 intake in 1256 women (88.8%), and lasted 11.7 +/- 6.4 (SD) days, range 2-55 days. One subject had blood transfusion due to excessive bleeding. The main side effects were nausea/vomiting (22.3%), abdominal pain (10.2%), headache/dizziness (4.1%) and diarrhea (2.8%). Fatal side effects have not been reported in this study. About 73% of subjects with complete abortion assessed the treatment as good to excellent. Even in the failed cases, 25-42% of subjects considered the treatment as good. Further studies are needed to determine the optimal dose of the RU486 regimen. It should be emphasized that the treatment must be used under close medical supervision in order to monitor the uterine bleeding.
Abortion, Incomplete↗
Gemcitabine in leukemia: a phase I clinical, plasma, and cellular pharmacology study.
PURPOSE: Phase I clinical and in vitro studies of gemcitabine (2',2'-difluorodeoxycytidine; dFdC) have demonstrated that the accumulation rate of dFdC 5'-triphosphate (dFdCTP) in mononuclear and leukemia cells is saturated when plasma or extracellular dFdC levels exceed 15 to 20 mumol/L. Thus, we designed a phase I study to maximize the accumulation of dFdCTP by leukemia cells by administering dFdC at 10 mg/m2/min, a dose rate calculated to produce steady-state plasma dFdC levels that exceed 15 to 20 mumol/L. PATIENTS AND METHODS: The treatment intensity was increased in patients (n = 22) with relapsed or refractory acute leukemia or chronic myelogenous leukemia (CML) in blast crisis by prolonging the infusion duration but maintaining the same rate. Doses of dFdC between 1,200 mg/m2 and 6,400 mg/m2 were administered weekly for 3 weeks. RESULTS: The maximum-tolerated dose was 4,800 mg/m2 infused over 480 minutes. The mean steady-state dFdC level in plasma of all infusions was 26.5 +/- 9 mumol/L (n = 19). The accumulation rates of dFdCTP in circulating leukemia cells varied greatly among patients but remained linear in eight patients infused for 120 to 240 minutes, and up to or beyond 360 minutes in five of eight additional patients. Elimination of dFdCTP was significantly related to its cellular concentration: blasts with greater than 450 mumol/L dFdCTP exhibited biphasic elimination, whereas blasts with lower dFdCTP concentrations exhibited linear kinetics. Biphasic elimination was associated with higher dFdCTP areas under the concentration-times-time curve (AUCs) and greater inhibition of DNA synthesis. CONCLUSION: Studies of the cellular pharmacology and pharmacodynamics of dFdC may be useful in optimizing protocol designs for leukemia.
Adolescent↗
[The study of the developmental potential of early embryonic cells of rabbit].
The developmental potential of rabbit embryonic cells was studied through making chimera by separate introduction of inner cell mass from 96-h-old p. c., 120-h-old p. c., and 144-h-old p. c. of grey rabbits into 96-h-old p. c. blastocysts of New Zealand white rabbits. A total of five overt chimeras were obtained including two fertile males, two fertile females and one sterile male, from the ICM cells of 96-h-old and 120-h-old embryos but none was obtained from 144-h-old cells. Histological examination of the gonad showed that the sterile chimera derived from 120-h-old ICM cells with an ovotestis on both sides. Follicles and seminiferous tubules developed in the cortex and medulla of the gonad, respectively. Neither of them developed into functional germ cells. Analysis of karyotypes of peripheral blood showed that both XX and XY coexisted in lymphocytes. These results indicated that the sterile male chimera was a XX/XY sex chimera derived from ICM cells of donor and recipients with different sex, so as to the chimera with XX and XY genotypic cells. From the results mentioned above we may conclude that the ICM cells at 120-h-old p. c. are still pluripotential, they can not only participate in development into somatic components but also develop into germ cells. The potential of 144-h-old p. c. ICM cells seems to be rather restricted.
Animals↗
Identification of intergeneric nucleo-cytoplasmic hybrid fish obtained from the combination of carp nucleus and crucian cytoplasm.
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Aging↗
Nuclear transplantation in teleosts. Hybrid fish from the nucleus of crucian and the cytoplasm of carp.
Hybrid fish are obtained from the combination of nucleus and cytoplasm from two genera of fresh-water teleosts using the technique of nuclear transplantation (i.e. the combination of the nucleus of crucian (Carassius auratus) and the cytoplasm of carp (Cyprinus carpio]. Morphological characteristics of these hybrid fish that have been examined so far indicate that some features such as barbs, pharyngeal teeth, the number of scales along the lateral line, and the number of vertebrae are similar to those of crucian. Some of the hybrid fish grow to normal adult fish.
Animals↗
Caries experience and oral health behavior in Chinese children with cleft lip and/or palate.
PURPOSE: The aims of this study were to investigate whether there were different caries levels in 3- to 6-year-old Chinese children who had a cleft lip compared to those with a cleft lip/palate. The goal also was to evaluate parental attitudes toward the feeding habits and oral health care for their children. METHODS: A cross-sectional study was carried out through a dental examination of a sample of children and a questionnaire to their parents. A sample of 104 3- to 6-year-old children (66 boys and 38 girls) with cleft lip, cleft palate or both were selected from those receiving pre-surgical treatment. Each child was examined and a short questionnaire was given to parents of the children. The form included questions about infant feeding practices, frequency consumption of specific drinks and, children's toothbrushing frequency. RESULTS: One hundred and four children were examined. Seventy-five percent had some caries experience and rampant caries was present in 26%. Children with cleft palate had a higher prevalence of rampant caries (30%) compared to those with cleft lip (12%). A multivariate analysis yielded feeding practices and mother's education as the variables significantly associated with caries and rampant caries. CONCLUSIONS: The results of this study show that: 1. Children with a cleft lip/palate have higher levels of dental caries compared to those with a cleft lip alone; 2. The two most important factors for dental caries were: a. whether the child had been bottle-fed and; b. the educational attainment level of the mother.
Bottle Feeding↗