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Biomedical subjects

R Lu

Publications and source records attributed to R Lu.

At least 127 records · Page 7Linked to original sources
PubMed1996

[A study on the loss of heterozygosity at the APC/MCC and DCC genetic loci in colorectal cancers].

To evaluate the role of APC, MCC and DCC genes in the development and progression of colorectal cancers, loss of heterozygosity (LOH) at these genetic loci was investigated in 41 surgically resected specimens of colorectal cancer by using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. LOH at APC or/and MCC was detected in 38.9% (14/38) of the informative cases; at the APC in 28.0% (7/25) and at MCC locus in 36.4% (8/22). LOH at DCC genetic locus was detected in 55.3% (21/38) of the informative cases. LOH rates DCC gene in the cancer specimens with lymphnode metastasis (80.0%) and in Dukes' stage III and IV (71.4%) were significantly higher than that in specimens without lymphnode metastasis (39.1%) and in Dukes' stage I and II (35.3%) (P < 0.05). Our results suggest that LOH at APC/MCC and DCC is the common genetic alterations in colorectal cancer and DCC genetic LOH assay may be useful in predicting the prognosis of patients with colorectal cancer.

Adenocarcinoma↗
PubMed1996

[Prevention of epidural scar adhesion following lumb spine operation].

Four biomaterials including pork fat (PF), glutaradehyde crosslinked pork peritonium (GCP), glutaradehyde cross-linked human amnion (GCA) and freeze-dried human amnion (FDA) dura were compared for their ability to prevent the dura from adhesion in 24 dogs. Noncontiguous laminectomies were performed on each dog. Laminectomized areas where the above mentioned 4 materials put randomly were served as experimental groups while laminectomized areas with autologous fat transplants put in place were served as standard control and empty control was set with the area left untreated. The formation of fibrosis and the adhesion of the dura were evaluated at 1, 2, 3, 4, 6, 12 weeks after operation by using a double-blind protocol. Methods of observation included gross anatomical evaluation, histological evaluation, computer-assisted image analysis, fibroblasts counting and measurement of SCEP. The results showed: 1. The epidural scar arose from the raw surface of erector spinal muscles and the bony edges created by the procedure; 2. Putting a suitable obstructor between the dura and the erector spinae muscle would make dura be exempted from adhesion; 3. The interpositional membrane should be tucked in between the bony edges in close proximity to the bony surface without leaving any room; 4. GCA seems to be efficient in preventing dural adhesion and reducing the invasion of the scar tissue in the spinal canal.

Amnion↗
PubMed1995

Identification and characterization of a prostaglandin transporter.

Carrier-mediated prostaglandin transport has been postulated to occur in many tissues. On the basis of sequence homology, the protein of unknown function encoded by the rat matrin F/G complementary DNA was predicted to be an organic anion transporter. Expression of the matrin F/G complementary DNA in HeLa cells or Xenopus oocytes conferred the property of specific transport of prostaglandins. The tissue distribution of matrin F/G messenger RNA and the sensitivity of matrin F/G-induced prostaglandin transport to inhibitors were similar to those of endogenous prostaglandin transport. The protein encoded by the matrin F/G complementary DNA is thus preferably called PGT because it is likely to function as a prostaglandin transporter.

Amino Acid Sequence↗
PubMed1995

[Effects of lyophilized royal jelly on experimental hyperlipidemia and thrombosis].

Rat models with experimental hyperlipidemia were fed with lyophilized royal jelly 700 mg/kg body weight daily for six weeks. Results showed lyophilized royal jelly can reduce serum cholesterol level (P < 0.01) and increase high-density lipoprotein-cholesterol level (P < 0.05). Lyophilized royal jelly can also increase the red cell deformability (RCD) and decrease plasma fibrinogen level. Thrombus was formed less in trial animals than in controls with a statistical significance. It suggested lyophilized royal jelly can be used in preventing and treatment of hyperlipidemia, and improving highly-coagulant status of blood.

Animals↗
PubMed1995

The evolution of the implanted pacemaker's window to the world.

An implanted pacemaker can only communicate with the outside world through its window, i.e., the clinical programmer. Since its inception, the pacemaker has evolved from a non-programmable device to a complex device. Therefore, programming a modern implantable pacemaker could be very challenging for non-experienced or infrequent users. Various programmer-based automatic functions have been developed to reduce programming time and complexity and to obtain accurate measurements. With increasing interests in the telecommunications and information exchange, these programmer-based automatic functions are pushing forward a future vision that automatic pacemaker follow-up procedures via telecommunications are possible for patients located in any corner of the globe.

Biomedical Engineering↗
PubMed1994

In vitro investigation of blood compatibility of Ti with oxide layers of rutile structure.

Structure characteristics of titanium oxide layer on titanium matrix were investigated by Rutherford Backscattering Spectroscopy (RBS), Auger Electron Spectroscopy (AES) and X-ray diffraction. It has been identified that the titanium oxide layers had rutile structure. The blood compatibility of the titanium oxide layers of different thickness was studied by blood clotting time measurement. It was shown that as the thickness of the titanium oxide layers increased, blood compatibility of these layers was obviously improved.

Animals↗
PubMed1993

Roles of sulfhydryl and disulfide groups in the binding of CP-55,940 to rat brain cannabinoid receptor.

The roles of sulfhydryl and disulfide groups in the specific binding of synthetic cannabinoid CP-55,940 to the cannabinoid receptor in membrane preparations from the rat cerebral cortex have been examined. Various sulfhydryl blocking reagents including p-chloromercuribenzoic acid (p-CMB), N-ethylmaleimide (NEM), o-iodosobenzoic acid (o-ISB), and methyl methanethiosulfonate (MMTS) inhibited the specific binding of [3H]CP-55,940 to the cannabinoid receptor in a dose-dependent manner. About 80-95% inhibition was obtained at a 0.1 mM concentration of these reagents. Scatchard analysis of saturation experiments indicates that most of these sulfhydryl modifying reagents reduce both the binding affinity (Kd) and capacity (Bmax). On the other hand, DL-dithiothreitol (DTT), a disulfide reducing agent, also irreversibly inhibited the specific binding of [3H]CP-55,940 to the receptor and about 50% inhibition was obtained at a 5 mM concentration. Furthermore, 5 mM DTT was abelt to dissociate 50% of the bound ligand from the ligand-receptor complex. The marked inhibition of [3H]CP-55,940 binding by sulfhydryl reagents suggests that at least one free sulfhydryl group is essential to the binding of the ligand to the receptor. In addition, the inhibition of the binding by DTT implies that besides free sulfhydryl group(s), the integrity of a disulfide bridge is also important for [3H]CP-55,940 binding to the cannabinoid receptor.

Animals↗
PubMed1992

An investigation of the composite resin/porcelain interface.

Failures at composite resin/porcelain interfaces under shear-like loading were examined. Porcelain surfaces were treated with hydrofluoric acid and/or one of two silane coupling agents, using two different composite resin cements. The results showed that after seven days storage, bond strengths of specimens which had undergone porcelain surface treatment were greater than the cohesive strength of the porcelain itself, resulting in brittle fracture of the porcelain. The diluted restorative composite resin performed as well as the commercial composite resin cement. Silane pretreatment of porcelain was important as the bond strength of etched/silane primed specimens was significantly higher than the etched only specimens. However, one primer appeared to be more efficient than the other in bond promotion. Some explanations for the differences in bond strengths are offered.

Acid Etching, Dental↗
PubMed1991

A method for obtaining a pure population of t6/t6 mouse embryos prior to developmental arrest.

Developmental delay, as the result of ovariectomy, causes mouse blastocyst embryos obtained from +/t6 inter se matings to separate into two distinct populations when placed into outgrowth medium. One population remains as free floating embryos for a significantly longer period of time than the other population. Based upon their phenotypic expression following attachment and outgrowth, the former population was considered to be composed entirely of t6/t6 embryos and the latter, to be composed of +/+ and +/t6 embryos (Nadijcka et al., '81). In the present study, two-dimensional gel electrophoresis identified the embryos which were delayed in attachment as t6/t6 embryos since they synthesize only p63/6.9a, a product of the Tcp-1a locus which is unique to t-haplotypes. The early attaching embryos, assumed to be +/+ and +/t6, synthesize both p63/6.9a and b. The p63/6.9b protein is coded for by Tcp-1b on the wild-type homologous chromosome. Control +/+ blastocyst embryos synthesize only p63/6.9b. The data show that t6/t6 embryos can be identified prior to their lethal period and, thus, subjected to comparative studies to determine the cause of their lethality. Developmental delay is the first method established to enable one to unambiguously identify t6/t6 embryos prior to developmental arrest.

Animals↗
PubMed1991

Preliminary clinical trials of a computer-based cardiac arrest alarm.

The use of a high reliability cardiac arrest alarm utilising the continuously monitored values of patient heart rate and mean arterial blood pressure is described, based on a sample of 167 patients monitored for a total of 5116 h. The analogue heart rate and mean blood pressure signals are sampled at 1 s intervals, and a smoothing algorithm is applied to each of the resulting series which rejects artefacts, and identifies slope and step changes in each. Certain combinations of events in the 2 series, occurring within a preset time window, determine whether a cardiac arrest alarm or warning signal should be activated by the system. A total of 30 acute events occurring in 14 patients during the course of the study were each identified within 10 s. No cardiac arrest event was misdiagnosed by the algorithm during the period of the study. The algorithm also generates warnings which may have predictive value, and which will be the subject of further research. A final false alarm rate of about 1/200 h of monitoring was observed in adults (1/50 h in children), with evidence that these rates could be substantially improved.

Algorithms↗
PubMed1991

[Preliminary study on soilless cultivation techniques of Panax quinquefolium L].

Our experiment has shown 1. Vermiculite with sand (volume 1:1) is a good substrate of soil for American Ginseng. The yield and contents of ginsenoside of American ginseng in this soilless substrate are a little higher than those in ordinary soil. 2. This kind of substrate can be used continuously with fewer occurrences of insect pest and plant diseases and contributes significantly to the reduction of production cost.

Ginsenosides↗
PubMed1990

[Effects of concentration and ratio of N, P and K on seedlings of Panax quinquefolium L].

Results of the orthogonal experiment of N, P and K are as follows: (1) The highest growth rate occurs in treatment 4 (N100ppm, P25ppm, K250ppm) and other features are also good. So this treatment can be used in hydroponics of seedling of P. quinquefolium. (2) The influences of N, P and K concentration on the contents of ginsenosides in different parts of seedling are different. The content of ginsenosides in aerial part is 14.72-16.72%, higher than 3.24-4.00% in root.

Ginsenosides↗
PubMed1989

Ca2+-dependent structural changes in bovine blood coagulation factor Va and its subunits.

The calcium dependence of the structures of bovine blood coagulation factor Va and its subunits (Vh and Vl) has been examined spectroscopically in order to characterize the conformational changes which accompany the binding of Ca2+ to Vh and Vl to form factor Va. The far-UV CD spectra of the isolated subunits indicate that the secondary structures of both Vh and Vl are predominantly beta-sheet (greater than 45%), with little alpha-helix content (less than 15%). No change in the far-UV CD spectrum was observed when factor Va was formed by the addition of Ca2+ to an equimolar mixture of Vl and Vh. Hence, no detectable change in secondary structure occurs during the formation of factor Va. In contrast, the addition of Ca2+ to an equimolar mixture of Vh and Vl caused a small (2%) increase in the total intrinsic fluorescence intensity and a blue shift in the emission spectrum that resulted from a tertiary structural change and/or the association of nonpolar surfaces at the subunit interface. This fluorescence change correlated closely with the appearance of functional factor Va, since the rate of the spectral change was the same as the rate of recovery of cofactor activity, and since both were half-maximal near 50 microM Ca2+. This fluorescence change required both subunits, was reversed by the addition of EDTA, and was observed only with metal ions that can substitute for Ca2+ in reconstituting factor Va activity from Vh and Vl (Mn2+ and Tb3+; not Mg2+). When a sample containing ANS (8-anilino-1-naphthalenesulfonate) and an equimolar mixture of calcium-free Vh and Vl was titrated with Ca2+, the ANS emission intensity decreased by about 30%, most likely because the association of Vl and Vh caused nonpolar regions at the subunit-subunit interface to become inaccessible for ANS binding. The calcium dependence of this spectral change yielded a Kd of 51 +/- 2 microM, and the rate of the decrease in ANS fluorescence occurred at nearly the same rate as the recovery of factor Va activity. Thus, both intrinsic and extrinsic fluorescence data, as well as other data, indicate that the calcium binding site in factor Va has an apparent Kd of 50 microM under our conditions and that the calcium-mediated binding between Vl and Vh involves hydrophobic interactions between the subunits.(ABSTRACT TRUNCATED AT 400 WORDS)

Anilino Naphthalenesulfonates↗