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Biomedical subjects

C Luo

Publications and source records attributed to C Luo.

159 records · Page 9Linked to original sources
PubMed1992

[Preparation of human placenta microvillous membrane and the study of its transferrin receptor].

Human placenta microvillous membrane (PMM) was prepared by differential centrifugation and by sucrose gradient centrifugation, and the transferrin receptor (TfR) was studied using the receptor radioassay with 125I-transferrin as a radioligand. The factors affecting ligand-receptor binding reaction and the characteristics of TfR were also studied. The result showed that there was no significant differences (P > 0.1) in specific binding rates of 125I-transferrin to its receptor between the two membrane preparations, indicating that both of them could be used for TfR analysis, but the method of differential centrifugation was more simple and less time consuming. The study of TfR in sixty cases showed that the TfR binding sites on PMM and Bmax were 3.53 +/- 1.98 x 10(12) sites/mg membrane protein and 6.33 +/- 4.21 x 10(-12) mol/mg membrane protein, respectively. The Kd was 4.95 +/- 3.39 x 10(-9) mol/L, and the highest specific binding was 26% with nonspecific binding less than 3%. The conditions for ligand-receptor binding reaction were optimized when the concentrations of membrane protein and the 125I-transferrin in each test tube were 50 micrograms and 50,000 cpm (specific radioactivity being 2109 kBq/micrograms transferrin) respectively the incubation time was 30 min, and the concentration of polyethylene glycol added for separating B/F was 12% (W/V). transferrin binding to its receptor was characterized by high affinity, high specificity and being saturated.

Cell Membrane↗
PubMed1992

Construction of an Rb gene expression plasmid.

We obtained an 844 bp Bg1II fragment from an Rb cDNA clone and inserted it into the expression vector pWR-13 to construct an Rb gene expression plasmid. When the Rb Bg1II fragment was fused in-frame into pWR-13, it was operated by a Lac Z promoter and produced a fusion protein which consisted of expressed Rb protein and a small peptide from Lac Z. The recombinants were transformed into E. coli with the CaCl2 method, screened by in situ hybridization, and restriction mapped. Total cellular protein of transformed clones was analyzed by SDS-PAGE and Commassie blue staining. The sense clones showed a unique band at 28,000. On Western blot, this band specifically reacted with 125I-labelled antibody against synthetic Rb peptide. This protein comprised more than 5% of total bacterial protein.

Amino Acid Sequence↗
PubMed1991

[Investigation of impairment of neutrophil's phagocytosis and bactericidal function in rats with iron deficiency].

Studies were made to determine the neutrophil's phagocytosis and bactericidal function in three groups of rats (control, iron deficiency, and iron supplement). Results showed that there were significant differences in values of chemiluminescence (CL) among three groups. The values of peak CL and five minutes integrated CL were markedly decreased in neutrophils of iron-deficient rats, accounting for only 41% and 32% of the control's values respectively. These suggested that the activity of NADPH oxidase was decreased, and the function of respiratory burst of neutrophils was impaired. The activity of myeloperoxidase in the iron-deficient neutrophils was also significantly lower than that in the control cells. It constituted only 30% of the control's value, indicating that the bactericidal function of neutrophils was injured. One week after iron administration, the low values of the peak CL, the five minutes integrated CL and the activity of myeloperoxidase all went up apparently, but not reached the normal levels yet. The time the function of neutrophils in iron-deficient rats returned to normal may be related to the process of neutrophil maturation in bone marrow.

Anemia, Hypochromic↗
PubMed1991

[A study on the effectiveness of three common stabilizers of peracetic acid].

This paper reports the effectiveness of 0.1% (W/V) quinoline-8-ol, 0.5% (V/V) phosphoric acid and 0.5% (W/V) sodium pyrophosphate as stabilizers of stock solutions on peracetic acid. The three solutions were put separately as stabilizers into stock solutions of peracetic acid in the laboratory. They were stored at room temperature for approximately one year, and the percent of peracetic acid content was determined at regular intervals. Also, we made studies on different concentrations of phosphoric acid for different prescriptions of peracetic acid. The results show that 0.1%, 0.3% and 0.5% (V/V) phosphoric acid and 0.5% (W/V) sodium pyrophosphate were not effective stabilizers for the stock solutions of peracetic acid. Therefore, phosphoric acid or sodium pyrophosphate is not an effective stabilizer in stockpiling stock solutions of peracetic acid.

Diphosphates↗
PubMed1991

[Observation of curative effect of refined interferon-alpha on viral pneumonia in infants].

Fifteen cases of viral pneumonia in infants were treated with refined interferon-alpha and antibiotics. Clinical symptoms of the cases with IFN-alpha were relieved in 1.40-2.79 days, earlier than those of the control. Clinical recovery time was on the average shorter than that of the control by 1.9 days, and complete recovery by 1.5 days. The difference is statistically significant. It suggested that the clinical effect of IFN-alpha together with antibiotics is better than that of antibiotics alone. There was no significant change between the experimental and control groups in absolute lymphocyte count Ig and T-cell, but OKT3 increased and OKT8 decreased slightly. The study shows that IFN is an effective and safe administration for viral pneumonia.

Anti-Bacterial Agents↗
PubMed1990

[Survey of Bacillus thuringiensis and Bacillus sphaericus from soils of four provinces of China and their principal biological properties].

A number of isolates of Bacillus thuringiensis and Bacillus sphaericus were obtained from soils of Southwestern Area and Shaanxi Province of China. Among isolates of B. thuringiensis were under 13 sorts of serotype in total of 23 sorts of B. thuringiensis and about 20% of auto-agglutinate strains. Rules of ecologic distribution of two sorts of bacteria were analysed. Toxicities on six species of insects, morphology and crystal proteins of B. thuringiensis, as well as toxicities, morphology and crystal proteins of B. sphaericus, were investigated. 22 strains of more efficient of B. thuringiensis and 2 strains of more efficient of B. sphaericus were obtained. It was shown that B. thuringiensis is actually soil microorganism, and resource of B. thuringiensis is much fruitful in Southwestern Area of China.

Bacillus↗
PubMed1990

[Effect of nutritional support of extensively burned patients with splenico-stomachictonic].

From 1983-1988, 20 cases of extensive burns were administered Splenico-Stomachictonic to regulate gastrointestinal function. The burns were above 80% total body surface area and/or third degree burn area above 50%. 18 cases of the same conditions in the same period served as the control. After 10 days, the therapeutic group had a total effective rate of 95%, and the control group had a total effective rate of 67% (P less than 0.05). The marked efficiency of the therapeutic group was 75% and the control group was 38% (P less than 0.05). The survival rate of the therapeutic group was 65% and the control group was 33%. These results suggested that the traditional Chinese Splenico-Stomachictonic medicine could bring to the extensive burn patients good gastrointestinal function, which helps improve nutritional status.

Adolescent↗
PubMed1990

[Influence of iron deficiency anemia on development of thymus and spleen and adenosine deaminase activity in rats].

Models of rats with iron deficiency anemia (IDA) were established, and changes in development of the thymus and spleen and adenosine deaminase (ADA) activity in them studied. The size and weight of the thymus in IDA rats were decreased, which suggested that the development of the thymus was lowered; but the size and weight of the spleen in IDA group were increased. ADA activities of the thymus and the spleen in IDA rats were significantly decreased by 32.98% and 25.89%, respectively. One week after iron supplement, the weight of the thymus and spleen in IDS group returned to normal level (P greater than 0.05), and their ADA activity also significantly increased, but ADA activity of the thymus tissue did not return to the normal. The results suggested that the changes in ADA activity of the thymus and spleen tissues were related to iron deficiency. Stepwise regression analysis suggested that there was a negative correlation between ADA activity of the thymus tissue and FEP/Hb ratio.

Adenosine Deaminase↗
PubMed1989

[Proteins and proteinase-resistant polypeptides of delta-endotoxins from Bacillus thuringiensis and their insecticidal activity].

Proteins, solubility in alkaline buffer and proteinase-resistant polypeptides (PRP) of parasporal crystals (delta-endotoxin) from Bacillus thuringiensis were investigated. 19 sorts of crystals were divided into 7 types. Difference of crystalline proteins were coincident with their solubility and PRP. The characters of the protein, solubility and PRP were subspecies-specific basically, but in a few of crystals they were strain-specific. There was a closed relation between the biochemistry property of crystal protein and the toxicity in 2 species of insects. Crystal with protein of MW 130-138 kD kD or MW 130-138 kD and 60-65 kD, and PRP of MW 68-75 kD were high toxic in Bombyx mori (Lepidoptera), but most of them only showed weak or no toxicity in Culex fatigans (Diptera). Crystals containing more than 3 sorts of proteins with MW 15-138 kD in major protein and MW 35-75 kD in minor protein and PRP of 35-65 kD had very strong toxicity in Culex fatigans, but no toxicity in Bombyx mori. The construct of the crystal protein and the importance of the character in protein and PRP for the selection of expected strain and for the work of genetic engineering in Bacillus thuringiensis were discussed.

Animals↗
PubMedDate not supplied

A novel applicator for low-dose-rate brachytherapy of gynecological cancers.

The standard low-dose-rate (LDR) delivery system utilized in the definitive management of patients with cervical carcinoma involves an intrauterine tandem and a pair of vaginal colpostats (ovoids). This well-known application system may deliver inadequate dosage if the tumor extends to the lower vaginal mucosa. During the gauze packing of the ovoids, either operator error or narrowing of the vaginal apex can result in mal-alignment of the colpostats and subsequent inadequate dosing to the ecto-cervix. A novel vaginal cylinder has been designed to address these concerns. Beginning January 1, 2001, patients with cancer of the cervix, endometrium, or vagina requiring LDR brachytherapy have been enrolled into an institutionally sanctioned clinical trial. As of May 31, 2001, a total of 11 patients have been entered but only 10 were successfully implanted with the test device. Patient follow-up has ranged from 0.81 years to 1.2 years (median: 0.96 years). Using our study applicator, all patients received within 10% of the preimplant prescribed dose to tumor. Also, no one had cumulative dosage that exceeded 10% of the maximum allowed dose to the critical normal tissues. Thus far, all study patients have had no clinical evidence of persistence/recurrence of disease or complications from treatment. The preliminary results presented herein clearly demonstrate the feasibility of this novel LDR vaginal cylinder in the treatment of a variety of clinical situations involving gynecological cancers. Our institutional trial is continuing.

Adult↗
PubMedDate not supplied

Case definitions for paediatric AIDS: the Zambian experience.

For the purpose of surveillance of the acquired immunodeficiency syndrome (AIDS) in developing countries, the World Health Organization (WHO) has recommended criteria for the clinical case definition of AIDS in adults and children. In a preliminary examination of children in Zambia a number of patients with obvious AIDS did not fit the published WHO case definition for paediatric AIDS. Based on this the Zambia National AIDS Surveillance Committee designed local criteria for the clinical case definition of paediatric AIDS. We compared the Zambian criteria with the WHO criteria for the diagnosis of paediatric AIDS by studying 134 consecutively admitted children to one of the paediatric wards at the University Teaching Hospital in Lusaka. Twenty-nine of the patients were HIV-1 seropositive and 105 were HIV-1 seronegative. Among the 29 HIV-seropositive patients, the Zambian criteria identified 23, and the WHO criteria identified 20 children as having AIDS. The 105 HIV-seronegative children were classified as having AIDS in 9 cases by the Zambian criteria and in 38 cases by the WHO criteria. These results give the Zambian criteria for the diagnosis of AIDS a sensitivity of 79.3%, a specificity of 91.4% and a positive predictive value of 86.8% compared to a sensitivity of 69%, specificity of 64% and a positive predictive value of 38% for the WHO criteria. The current WHO criteria are inadequate for the diagnosis of paediatric AIDS. The need to refine the WHO criteria for the diagnosis of paediatric AIDS is discussed.

AIDS Serodiagnosis↗
PubMedDate not supplied

Differential processing of homologues of the small subunit of ADP-glucose pyrophosphorylase from barley (Hordeum vulgare) tissues.

ADP-glucose pyrophosphorylase (AGPase), a two-gene-encoded enzyme, is the key component of starch synthesis in all plants. In the present study, we have used an E. coli expression system for the (over)production of proteins derived from both full length and specifically truncated cDNAs encoding small subunits of AGPase from seed endosperm (AGPase-B1) and leaves (AGPase-B2) of barley (Hordeum vulgare). Based on immunoblot analyses, the molecular mass of the expressed AGPase-B1 (52 kD) was similar to that from endosperm extracts, whereas the expressed AGPase-B2 (56 kD) was larger than that in barley leaves (51 kD). Expression of truncated cDNAs for both the seed and leaf proteins has allowed for a direct verification of molecular masses that were earlier proposed for mature AGPases in barley tissues. The data suggest that seed AGPase-B1 does not undergo any post-translational proteolytic processing in barley, whereas the leaf homologue is processed to a smaller protein. Possible implications of these findings are discussed.

Cloning, Molecular↗
PubMedDate not supplied

Molecular cloning and spatial expression of an ApL1 cDNA for the large subunit of ADP-glucose pyrophosphorylase from Arabidopsis thaliana.

A cDNA, ApL1a, corresponding to a homologue of the large subunit of ADP-glucose pyrophosphorylase (AGPase), has been isolated/characterised by screening a cDNA library prepared from leaves of Arabidopsis thaliana, followed by rapid amplification of cDNA 3'-ends (3'-RACE). Within the 1685 nucleotide-long sequence (excluding polyA tail), an open reading frame encodes a protein of 522 amino acids (aa), with a calculated molecular weight of 57.7 kDa. The derived aa sequence does not contain any discernible transit peptide cleavage site motif, similarly to two other recently sequenced full-length Arabidopsis homologues for AGPase, and shows ca. 58-78% identity to homologous proteins from other plants/tissues. The corresponding gene was found to be expressed in all tissues examined (rosette and stem leaves, stems, flowers and fruits). The ubiquitous expression of the gene is consistent with its critical role in starch synthesis in Arabidopsis.

Amino Acid Sequence↗
PubMedDate not supplied

Constant expression of cyclooxygenase-2 gene in prostate and the lower urinary tract of estrogen-treated male rats.

Expression of cyclooxygenase-2 (E. C. 1.14.99.1) in prostate and the lower urinary tract (LUT) of the neonatally estrogenized male rat has been studied by using a COX-2's PCR fragment of 724 nt spanning 3 introns and a 478nt internal standard for quantitative RT-PCR. The same fragment of 724 nt was used for RNA probe in Northern hybridization. Neonatal estrogenization (10 microg/day of diethylstilbestrol on days 1-5) had no effect on COX-2 expression in prostatic urethra, prostatic lobes, or bladder. Acute estrogen treatment of castrated animals did not induce COX-2 expression, either. In addition the differential expression of basal level of COX-2 in the different lobes of prostate in normal rat was demonstrated. Our results suggest a constant expression of COX-2 gene in prostate and the lower urinary tract of the neonatally estrogenized (neoDES) rats. The present study indicates that the increased expression of COX-2 is probably not essential for the estrogen-driven development of stromal inflammation or hyperplastic and dysplastic alterations in the prostate of neoDES rats.

Animals↗