Search PubMed⌕ Search

Biomedical subjects

L Ren

Publications and source records attributed to L Ren.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Cardiac operation via subaxillary and anterolateral subaxillary thoracotomy with cardiopulmonary bypass].

From March 1995 to August 1996, 50 patients underwent cardiac operation through subaxillary and anterolateral subaxillary thoracotomy with cardiopulmonary bypass. 17 had atrial septal defect, 26 ventricular septal defect, 3 mitral stenosis and insufficiency, 1 isolated mitral insufficiency, 1 double chamber of right ventricle, 1 partial common atrioventricular canal, and 1 cor atriatriatum. All operations were successfully performed without technical difficulty. The cardiopulmonary bypass time was 40.19 +/- 17.17 minutes with aortic cross-clamping time of 22.59 +/- 11.06 minutes. There were no operative death and complications. In conclusion, the subaxillary and anterolateral subaxillary thoracotomy incision appears to be a minimally invasive, safe, effective and cosmetic alterative to median sternotomy for cardiac operation.

Adolescent↗
PubMed1997

[Electron microscopy of elastic system fibers in the rat mandibular joint].

We study the Elastic System Fibers (ESFs) in the rat mandibular joint using light microscope and image analyzer system and Electron Microscope. The results showed that the ESFs in the articular disc and capsule were more than in the articular cartilage. In addition, microfibrils and elaunin were the principal ESFs in all the articular components. The microfibrils in the articular surfaces ran at nearly right angle to the collagen fibers. The ESFs beneath the articular surfaces and the other articular components showed no specific directivity. ESFs construct an extensive fibers network in the disc and the capsule.

Animals↗
PubMed1997

[Studies on the voltammetric behaviour of barbaloin and its application].

In 0.1 mol.L-1 H2SO4 solution, a well-defined reduction wave of barbaloin was obtained by single-sweep osciflopolarography. The peak potential was shown to be -0.75 V (vs SCE). The peak current is proportional to the concentration of barbaloin over the range of 2.0 x 10(-7)-6.0 x 10(-6) mol.L-1. The detection limit is 2.0 x 10(-7) mol.L-1. The voltammetric behaviour of the system was studied by linear sweep and cyclic voltammetry. The adsorption coefficient beta was 1.91 x 10(5). The interaction factor alpha was 1.12. The system is a reversible adsorption wave.

Aloe↗
PubMed1997

[Interstitial tubercle in Chinese and Japanese young adults]

A comparative study on the incidence of interstitial tubercle from standardized stone casts of 160 Chinese and 190 Japanese young adults,ages from 20-30.The following results were obtained:(1)No significant difference in the incidence of interstitial tubercle on maxillary first premolar between Chinese and Japanese groups(P>0.05),but on maxillary second premolar,Japanese is higher than Chinese(P<0.05).(2)The incidence of interstitial tubercle on maxillary first premolar is higher than second premolar in two groups(P<0.05).(3)The intestitial tubercle occurs in unilateral more frequently than in bilateral.The incidence of maxillary first premolar in mesial of occlusal is higher than in distal.No difference between mesial and distal on occlusal of maxillary second premolar in the Chinese group,and the incidence in mesial is higher than in distal in the Japanese group.

Journal Article↗
PubMed1997

[Morphological study on occlusal grove of mandibular molar of Chinese adults]

During human evolution,the morphology of mandibular molar occlusal grooves have changed from the pattern "Y" to pattern "+".Six types of occlusal grooves were classified as:Y5,Y4,+5,+5,X5 and X4. Using computer analysis,we get the result.(1)The rate of "Y5" in first mandibular molar is the highest,the rate of "X4" is the lowest.(2)The rate of "+4" in second mandibular molar is the highest,while the rate of "Y5" is the lowest. (3)The rates of each type groove between male and remale have no significant difference.Our conclusion coincides in the evolution of human mandibular molar,that is helpful to direct the clinic and anthropology study.

Journal Article↗
PubMed1997

[Rapidly expanded skin tube studied by histological and stereological observations].

In order to investigate the histological and stereological change of the rapidly expanded skin tube, 15 Japanese Long Ear Rabbits were divided into 3 groups: (1) Rapid expansion group, injecting once a day for 7 days; (2) Routine expansion group, injecting every 3 days for 21 days and (3) Control group, no expander implanted. The results showed that: in the rapid expansion group, the thickness of the epidermis and dermis were both increased, fibroblast proliferation was active, a large amount of new capillaries was observed, the collagen fiber was in loose type, and the mitochondria and rough endoplasmic net of epithelial cell were increased. In the routine expansion group, similar changes were observed. The vascular density and volume fraction were significantly higher in rapid expansion group than those in the control group (P < 0.05). It was concluded that the rapid expansion of skin tube was feasible.

Animals↗
PubMed1996

Dimethyl formamide (DMFA) and ethylene glycol (EG) are estrogenic in rainbow trout.

During our studies on the effects of environmental estrogenic chemicals on vitellogenin gene expression in fish, dimethyl formamide (DMFA) and ethylene glycol (EG) were used as solvents to dissolve and deliver hydrophobic beta-estradiol or nonylphenol. Control groups were injected with water only. It was surprising to find that in certain doses, Vg mRNA from control fish can be induced by DMFA or EG alone. This suggested that DMFA and EG are weak estrogens.

Animals↗
PubMed1996

Effects of estrogen and nonylphenol on the post-transcriptional regulation of vitellogenin gene expression.

Estrogenic chemicals have drawn considerable attention over the past several years because they are known to be responsible for increased breast and prostate cancer. Vitellogenin expression driven by estrogen has been becoming a model for studying estrogenic effects in aquatic species. For the first time, we showed evidence that, without stimulation, vitellogenin mRNA precursor is expressed in both male and female immature fish. After 4 h, in fish treated with estradiol, the vitellogenin mRNA was synthesized and the precursor mRNA began to disappear. The environmental chemical, nonylphenol, showed the same effect on the vitellogenin gene expression as estrogen. It is suggested that estrogen and nonylphenol may be involved in a post-transcriptional regulation process -- possibly in the initiation of pre-mRNA splicing.

Amino Acid Sequence↗
PubMed1996

Photoinduced effects of polycyclic aromatic hydrocarbons on Brassica napus (Canola) during germination and early seedling development.

It has recently been demonstrated that light dramatically enhances the toxicity of polycyclic aromatic hydrocarbons (PAHs) to the duckweed Lemna gibba L. G-3 (L. Ren, X.-D. Huang, B.J. McConkey, D.G. Dixon, and B.M. Greenberg, 1994, Ecotoxicol. Environ. Saf. 28, 160-171). To extend this research to terrestrial plants, Brassica napus L. (oil seed rape) seeds were germinated in the presence of three PAHs; anthracene (ANT), benzo[a]pyrene (BAP), and fluoranthene. The chemicals were applied both in intact form and following photomodification in UV-B radiation; toxicity was assessed in simulated solar radiation (SSR), a light source with a visible light:UV-A:UV-B ratio similar to that of sunlight. Germination efficiency, root and shoot growth, and chlorophyll content, measured after 6 days of exposure, were used as toxicity endpoints. Intact and photomodified PAHs had little impact on shoot fresh weight or chlorophyll content, but markedly inhibited root fresh weight, with the photomodified PAHs having greater impacts than the intact PAHs. The decline in root fresh weight was not attributable to a decline in germination frequency or delayed germination. However, the seedlings produced shorter roots in the presence of either intact or photomodified PAHs. To explore the role of actinic radiation on PAH toxicity, seedlings were incubated in SSR, visible light and darkness with either intact or photomodified PAHs. Inhibition of root growth was only achieved by the intact chemicals if actinic radiation was present. However, with photomodified ANT or photomodified BAP, root fresh weight accumulation was inhibited in SSR, visible light and darkness. Thus, intact PAHs are hazardous to terrestrial plants in the presence of light, but once the compounds are photomodified, actinic radiation is no longer an absolute requirement for phytotoxic activity.

Brassica↗
PubMed1996

Porous hydroxyapatite reinforced with collagen protein.

Porous hydroxyapatite (HAP) with certain porosity and pore size was prepared, and incorporated with bovine collagen protein. The composition and structure of the HAP was confirmed by X-Ray Diffraction (XRD) and ICP. Scanning Electron Microscopy (SEM), mechanical tests and in vitro degradation were performed. Collagen protein with low antigenicity was obtained from bovine tendon by enzyme digestion, and was then forced to fill in the HAP matrix to form composites. Scanning Electron Microscopy (SEM), Mechanical tests and in vitro degradation were performed. The test results show that first, HAP thus made has specific pore size and directions; second, mechanical properties of the composites have been markedly improved; third, the in vitro degradation rate of the composite is almost the same as and mainly controlled by the degradation rate of collagen.

Animals↗
PubMed1996

In vivo estrogenic activity of nonylphenol in rainbow trout.

Estrogenic compounds have shown to induce specific endocrine system responds in various species. The protein vitellogenin and its corresponding mRNA have been shown to be induced by estrogenic chemicals in aquatic species. In this investigation the estrogenic chemical nonylphenol was studied in rainbow trout for lethality, estrogenicity, and persistence of effects through the use of reverse transcription polymerase chain reaction of liver vitellogenin mRNA. These results show that nonylphenol produces estrogenic effects in rainbow trout at concentrations well below the LC50.

Animals↗
PubMed1995

Second malignant neoplasms in long-term survivors of childhood rhabdomyosarcoma.

BACKGROUND: The occurrence of second malignant neoplasms (SMNs) in successfully treated pediatric patients with cancer has been an area of increasing concern because survival of these patients has improved with intensification of therapy. Therefore, the incidence of SMNs in long term survivors of childhood rhabdomyosarcoma (RMS) was studied. METHODS: From 1970 to 1989, 210 newly diagnosed patients (median age, 9.7 years; range, 1 month to 27 years) with RMS were treated at Memorial Sloan-Kettering Cancer Center (New York, NY). Multimodality treatment included chemotherapy, surgery, and radiotherapy, when indicated. There were 130 long term survivors (> 2 years off therapy) with a median follow-up of 9 years (range, 2-20 years). The cumulative dose of each chemotherapeutic agent and the radiation doses each patient received were reviewed. Statistical analysis was performed by comparison with the Connecticut Tumor Registry data. RESULTS: Seven patients developed a SMN, including three with acute nonlymphoblastic leukemia (ANLL) and four with solid tumors. Acute nonlymphoblastic leukemia developed a median of 4.5 years after diagnosis. Of the solid tumors, 3 developed within the radiation field at a median of 10 years after diagnosis, whereas the fourth occurred 9.3 years after initial diagnosis in a patient who did not receive radiotherapy. All seven patients with SMNs received total dactinomycin doses higher than the median (9.6 mg/M2) for the group. All three patients with ANLL received total cyclophosphamide doses higher than the median (16.8 g/M2). Moreover, six of the seven patients received a dose of radiotherapy greater than 4000 cGy. The standardized incidence ratio was: 17.07 (95% confidence interval, 6.68-35.18; P < 0.0001). CONCLUSIONS: Multimodality therapy has improved long term survival for patients with childhood RMS. The combination of high dose radiotherapy and chemotherapy appears to increase the risk for developing a second malignancy.

Adolescent↗
PubMed1995

Quality of life in phase II trials: a study of methodology and predictive value in patients with advanced breast cancer treated with paclitaxel plus granulocyte colony-stimulating factor.

BACKGROUND: Despite the clinical benefit that may be associated with reduction of tumor volume, chemotherapy may produce physical or psychological distress that could compromise a patient's quality of life. Although palliation may be as relevant as tumor response in patients with metastatic breast cancer, quality of life is not commonly evaluated in phase II clinical trials of new therapeutic agents. PURPOSE: We evaluated the utility of quality-of-life assessment in two phase II clinical trials of patients receiving paclitaxel (Taxol) and recombinant human granulocyte colony-stimulating factor (rhG-CSF) as salvage therapy for metastatic breast cancer. METHODS: A battery of instruments (i.e., Memorial Symptom Assessment Scale [MSAS], Functional Living Index-Cancer [FLIC], Rand Mental Health Inventory [MHI], Brief Pain Inventory [BPI], and Memorial Pain Assessment Card [MPAC]) designed to capture information about social, psychological, and functional aspects of quality of life, as well as symptom prevalence and distress, was completed prior to treatment; serial assessments were obtained at regular intervals during the treatment period. Univariate and multivariate analyses were performed evaluating base-line quality-of-life parameters and standard prognostic factors in relation to outcome measures of survival, tumor response, and toxicity. For 30 consecutive patients with extensive prior chemotherapy for metastatic disease, longitudinal data were analyzed associating tumor response to changes in quality-of-life scores throughout the course of treatment with paclitaxel. RESULTS: Base-line scores of two validated quality-of-life instruments, the MSAS and the FLIC, independently predicted the overall survival (P < .01 for each). In this model, however, neither standard prognostic factors nor quality of life instruments predicted the likelihood of tumor response or the probability of encountering grade 3 or grade 4 nonhematologic toxicity. With serial assessments of quality of life, the majority of patients who achieved partial tumor response or stable disease reported improved or unchanged quality-of-life scores, while those patients with progressive disease experienced rapid deterioration in quality of life. CONCLUSIONS: Base-line quality-of-life assessment may provide prognostic information distinct from that obtained through standard prognostic indicators alone. The combination of two factors--extent of disease and a base-line quality-of-life assessment--predicted survival more accurately than either used separately. Evaluation of quality-of-life outcomes in relation to tumor response may illuminate previously unmeasured palliative effects of chemotherapy, such as pain relief, as well as the burdens it imposes. IMPLICATIONS: Information obtained from quality-of-life assessment in conjunction with phase II testing of new chemotherapeutic agents for metastatic breast cancer can guide quality-of-life evaluation planned in large, randomized future studies.

Adult↗
PubMed1995

Nuclear multicatalytic proteinase alpha subunit RRC3: differential size, tyrosine phosphorylation, and susceptibility to antisense oligonucleotide treatment.

Multicatalytic proteinases (MCPs) are macromolecular structures involved in intracellular degradation of many types of proteins. MCPs are composed of a 20S "core" which consists of both structural (alpha) and presumed catalytic (beta) subunits in association with complexes of accessory proteins. Immunohistochemical studies have shown MCP subunits to be largely cytoplasmic, although nuclear localization is also observed. Reverse transcription/polymerase chain reaction amplifications were performed with redundant primers to conserved regions within known subunits, in an attempt both to identify potential new subunits and to define the repertoire of subunits expressed in hepatocytes. No new subunits were identified, and we found that RRC3, an alpha subunit of MCPs which contains a putative nuclear localization signal (NLS), was the predominant alpha subunit expressed in hepatocytes and hepatocyte-derived cell lines. Antibodies were developed against a unique C-terminal peptide region of RRC3. Immunohistochemical studies using affinity-purified antibodies showed that RRC3 has both cytoplasmic and nuclear localizations. Immunoprecipitation/immunoblot analyses showed that a significant proportion of nuclear RRC3 was associated with the nuclear scaffold (NS). NS RRC3 showed a significantly smaller M(r) (24,000) than the cytoplasmic form (M(r) 28,000), and only the nuclear form contained phosphotyrosine. In metabolic labeling experiments with [32P]orthophosphate, the major nuclear and NS form observed showed an M(r) of 24,000, whereas no labeling of cytosolic RRC3 was observed. A minor 32P-labeled band of M(r) 28,000 was also observed in nuclei, and this M(r) 28,000 form was found in the soluble nuclear extract within MCP complexes. These results suggest that tyrosine phosphorylation of the cytosolic form (M(r) 28,000) rapidly triggers nuclear import, which is in turn quickly followed by conversion to the major M(r) 24,000 form associated with NS. Treatment with antisense oligonucleotides targeted to the initiation site of RRC3 reduced the growth of a hepatocyte-derived cell line by 95% and produced a marked morphological change (in the absence of overt toxicity). Under these treatment conditions, RRC3 mRNA was dramatically reduced. RRC3 protein was also dramatically reduced in the NS, but showed only a small reduction in cytosol, suggesting that the nuclear RRC3 may be important in cell growth and differentiation.

Amino Acid Sequence↗
PubMed1995

Nuclear scaffold-associated protease: in situ nuclear localization and effects of a protease inhibitor on growth and morphology of a ras-transformed hepatocyte cell line.

We have previously identified a multicatalytic protease (MCP) activity associated with the nuclear scaffold (NS) in hepatocytes and fibroblasts. When we used the chloromethylketone protease inhibitor AAPFcmk, which is targeted to chymotrypsinlike protease activity, we observed a dramatic inhibition of transformation of fibroblasts, with effects that were relatively selective for the NS fraction. Here, we undertook experiments to determine the effects of AAPFcmk on Simian Virus 40-immortalized CWSV1 cells compared with a ras-transformed hepatocyte cell line (NR4) derived from CWSV1. We used biotinAAPFcmk and fluorescent reagents to demonstrate a nuclear chymotrypsinlike protease activity, which is most prominent at the nuclear envelope. The ras-transformed NR4 cells were highly susceptible to growth inhibition in a dose-dependent manner, showing 85% growth inhibition at 50 mumol/LAAPFcmk. In contrast, the immortalized CWSV1 cells were not sensitive at the concentrations (10 to 50 mumol/L) of AAPFcmk tested. In subcellular fractionation studies, the inhibitory effects of AAPFcmk were confined to the NS fraction. The AAPFcmk-induced growth inhibition was accompanied by marked morphological changes in ras-transformed cells, without evidence of overt toxicity. No change in DNA content was observed, but a marked increase in organization of actin cytoskeletal elements was seen. These results suggest that a protease activity associated with the nuclear scaffold has important functions in controlling cytoskeletal filament organization and cell replication.

Amino Acid Chloromethyl Ketones↗
PubMed1995

[A comparative morphologic study of Carabelli cusp between Chinese and Japanese students.].

The study of teeth,dentition and occlusion is helpful to guide oral medical clinic and the study of anthropology.Our department of Osaka Dental University and had many items of research work about teeth,dentition and occlusion between Chinese and Japanese students.This article reports the study of Carabelli cusp.The results revealed:(1)the rate of Carabelli cusp is higher in Japanese than in Chinese and is higher in male than in female.(2)the rate of Carabelli cusp of the first maxillary molar of both side is very high.(3)The rate of Carabelli cusp is related to the height and the type of cusp numbers.These all illustrated the occurence of Carabeiil cusp were influenced by race, individual and the development of teeth.

English Abstract↗