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Biomedical subjects

G Lu

Publications and source records attributed to G Lu.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Observation of immune effect of 5 kinds of Denmark II lyophilized vaccines].

This paper reported five kinds of Denmark II lyophilized vaccines produced by 5 different biological production institutes. Through the double blind randomized trial in newborns after 1 year observation, the results demonstrated that all vaccines possessed the stability of heat tolerance and the 12 week tuberculin conversion rates of all group exceeded to 95%, and 1-year positive maintenance rates were in the range of 88.3%-96.1%, and the average diameter of induration was relatively large; the local reaction belonged to normal range; the swollen-lymph node rate was not high; the immune effect was satisfactory.

BCG Vaccine↗
PubMed1995

[Tension-stress effect on genesis and growth of the external anal sphincter].

The relationship between the length of the external anal sphincter (EAS) and the anal pressure was observed in 37 guinea pigs. The results showed that if the muscle was stretched from 100% to 300% of its original length, the resting anal pressure was kept relatively steady (steady phase), but the actively contracting pressure was proportionally increased; if from 300% to 370%, a sharp increase of resting anal pressure was developed (accelerating phase), but the actively contracting pressure would gradually decrease to zero; beyond 370%, the resting anal pressure remained unchanged (plateau phase), while in the muscle, the nerve fiber, muscle fiber and blood vessel were damaged and necrotic. However, if the muscle was continously stretched at the accelerating phase of the resting anal pressure for 6 days, the muscle could grow in length at a rate of 2mm/d. In the growth muscle, the muscle cell was hypertrophic, the Schwann's cell in the nerve fiber was generated and the blood vessel became abundant. Both transversely split sarcomere and longitudinally split sarcomere were seen in the muscle cell in electron microscope. This result has surgical importance for treatment of anorectal anomaly.

Anal Canal↗
PubMed1995

Technetium-99m MIBI uptake in recurrent parathyroid carcinoma and brown tumors.

Demonstrable parathyroid adenoma in delayed (3-hr) 99mTc-MIBI neck imaging and localization of 201Tl-chloride in brown tumors mimicking skeletal metastases have been reported. Technetium-99m-MIBI scintigraphy is currently the imaging modality of choice for localizing parathyroid tumors in patients with recurrent hyperparathyroidism. This report is a good example of the use of 99mTc-MIBI in the diagnostic work-up of a patient with recurrent hyperparathyroidism, which turned out to be due to parathyroid carcinoma rather than the initial histopathologic diagnosis of parathyroid adenoma. Additionally, the patient's total body 99mTc-MIBI and 99mTc-MDP bone images showed multiple focal lesions in the bone-mimicking metastases.

Adenoma↗
PubMed1995

[Mental status and personality of infertile women].

Mental status and personality were investigated in 130 infertile women from November 1992 to May 1993 in the infertility clinic of The Second Hospital of Hunan Medical University. Causes of their infertility attributed to female (n = 65), male (n = 53), unexplained infertility (n = 12). Fifty four fertile women were recruited as normal control. A women consulting questionnaire, Eysenck personality questionnaire (EPQ), symptom checklist-90 (SCL-90), self-rating anxiety scale (SAS) and Hamilton depressive scale (HDS) were used in this study. The result showed that any level of mental pressure were found in 83.8% of infertile women, and moderate and severe in 52%. In comparison with the control, the prevalence of psychiatric symptoms were significantly higher in infertile than fertile women (P < 0.01). Infertile women were more likely to suffer from severe depression and anxiety. Their mental status were more unstable than fertile women and correlated with their personality traits. Authors emphasized that not only the somatic treatment, but also the psychological consultation and mental support should be provided in the program of the infertility management.

Adult↗
PubMed1995

99Tcm-MIBI mammoscintigraphy of breast masses: early and delayed imaging.

Forty patients with breast mass and 10 female controls underwent double-phase (15 min and 3 h) 99Tcm-sestamibi (MIBI) imaging. Another four post-mastectomy patients with suspected metastases underwent total body imaging at 15 min. The 99Tcm-MIBI images of all 10 female controls showed symmetrical homogeneous radioactivity in both breasts. A focal area of increased 99Tcm-MIBI uptake in the breast tumour is considered as positive. Eleven breasts of 10 patients underwent total mastectomies with lymph node dissection, with one patient having bilateral mastectomy. These 11 breast tumours were confirmed to be infiltrating ductal carcinoma. All 11 breast carcinomas had positive early and delayed phase results with the exception of one patient who had only a focal increased uptake in early phase which happened to be the smallest size of carcinoma. Focal areas of positive MIBI uptake in the axillae in 4 of 10 patients were confirmed to be metastatic carcinoma of the breast. One patient with breast carcinoma underwent mastectomy whose 99Tcm-MIBI imaging was negative. Twelve patients undergoing excisional biopsy or lumpectomy of breast resulted in 7 fibroadenomas, 2 papillomas, 1 abscess, 1 granuloma and 1 chronic inflammation. Four of 7 fibroadenomas having hypercellularity histopathologically exhibited a focal MIBI uptake on double-phase imaging. One granulomatous disease had positive early phase but faded on the delayed image. The patients with absence of MIBI uptake included 3 fibroadenomas, 2 papillomas, 1 abscess, 1 chronic inflammation and 17 fibrous hyperplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Quantitation of P53 protein expression in gastrointestinal smooth muscle tumors. Clinicopathological correlation and prognostic significance.

Quantitative analysis of P53 protein expression was performed on paraffin-embedded tissues from 55 smooth muscle tumors of the gastrointestinal tract, using immunofluorescence and flow cytometry. No positive expression was found in normal smooth muscle tissues of the gastrointestinal tract. Over-expression of P53 gene was found in a significantly higher proportion in leiomyosarcomas (90%) and potentially malignant smooth muscle tumors (75%) as compared to leiomyomas (14%) (P < 0.005). The quantitation of P53 expression was found to be progressively enhanced in the sequence from leiomyoma through potentially malignant smooth muscle tumor to leiomyosarcoma (P < 0.005). It was markedly over-expressed when the mitotic counts ranged from one to more than one per 10 high power fields (P < 0.005) or the mild cytologic atypia was found (P < 0.005). The five-year survival rate was significantly higher in patients with low-expression of P53 than in those with over-expression of P53 (P < 0.005). It was suggested that P53 over-expression might be associated with the transformation of leiomyoma into leiomyosarcoma and could be used as an objective parameter in distinguishing the malignant from the benign and predicting the prognosis of patients with smooth muscle tumors of the gastrointestinal tract.

Adolescent↗
PubMed1995

Preparation and characterization of monoclonal antibodies against aflatoxin B1.

Five hybridoma cell lines producing monoclonal antibodies (MAb) against Aflatoxin B1 (AFB1) were established after fusion of mouse myeloma cells (SP-2/O-Ag-14) with spleen cells isolated from male BALB/c mice immunized with AFB1-BSA conjugate. Among these, one MAb, designated AFB1-2H8, was of the subtype IgG3 and the acidic fluid of which gave high dilution titers (1:5 x 10(5). The sensitivity of a competitive inhibition enzyme immunoassay (CIEIA) using AFB1-2H8 for AFB1 demonstrated that the linear range was 0.5-50 ng/ml and the minimum detectable concentration of AFB1 was 0.01 ng/ml. The specificity of the MAb was determined and showed no significant crossreaction with any of the metabolites tested. So th-- MAb and the CIEIA described may be useful in the detection of AFB1 in food and feed.

Aflatoxin B1↗
PubMed1994

Crystal structure of the FAD-containing fragment of corn nitrate reductase at 2.5 A resolution: relationship to other flavoprotein reductases.

BACKGROUND: In the biological assimilation of nitrate in plants and microorganisms, nitrate is reduced to ammonium by transfer of eight electrons in a two-step process. The first step of the pathway, the reduction of nitrate to nitrite, is catalyzed by nitrate reductase, a multi-redox cofactor enzyme which belongs to the class of flavoprotein pyridine nucleotide cytochrome reductases. The enzyme can be divided into three functional fragments that bind the cofactors molybdopterin, heme-iron and flavin adenine dinucleotide (FAD)/nicotinamide adenine dinucleotide (NADH). RESULTS: Here we describe the crystal structure of the recombinant cytochrome b reductase fragment of corn nitrate reductase, in complex with the cofactor FAD, determined to 2.5 A resolution. This catalytically competent fragment of nitrate reductase consists of two domains, the amino-terminal lobe, which binds FAD, and the carboxy-terminal lobe, which presumably binds NADH, connected by a linker region. CONCLUSIONS: Nitrate reductase belongs to the class of flavoprotein pyridine nucleotide cytochrome reductases, a subgroup in the family of ferredoxin reductase-like flavoproteins. Comparison with other members of this family reveals that large structural differences are found in the relative orientation of the cofactor binding lobes. This indicates that conformational changes might be important for biological function.

Amino Acid Sequence↗
PubMed1994

Role for glial cells in regulating the functional expression of neuropeptide Y (NPY) neurons in aggregate cultures derived from dissociated fetal brain cells.

A series of studies from our laboratory have established an aggregate culture system of fetal rat brain cells expressing neuropeptide Y (NPY) which can serve as a model to study the role of glia-neuron paracrine interactions in the developmental expression of NPY neurons. In this system, NPY production increases progressively with culture-age and it is induced by forskolin (FOR) and phorbol 12-myristate 13-acetate (PMA). We addressed the following question: Is the functional expression of the NPY neurons impaired in the absence of glial cells (particularly astrocytes) and if so, can secretory products of aggregates composed of the full complement of brain cells (intact aggregates) restore the function of the impaired NPY neurons? Aggregates were generated from 17-day-old fetal rat cortex and maintained in serum-free medium for 13-15 days. Cytosine arabinoside (CA; doses of 0.5-8 microM) was added to the cultures on day 1 and the effectiveness in elimination of glial cells was verified on day 15 by measuring the incorporation of 3H thymidine into DNA and by immunostaining for the astrocyte marker glial fibrillary acidic protein (GFAP). Basal NPY production and FOR (10 microM) + PMA (20 nM) stimulated production of NPY on days 13-15 were taken as functional criteria. FOR + PMA induced approximately 2-fold increase in NPY production in control cultures (no CA). CA inhibited both basal and FOR + PMA induced production of NPY and DNA synthesis in a dose-dependent manner: at 6 microM CA, basal NPY production was reduced by about 50%, FOR + PMA stimulated production of NPY and DNA synthesis were completely inhibited, and astrocytes were essentially eliminated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A single Arabidopsis GF14 isoform possesses biochemical characteristics of diverse 14-3-3 homologues.

Arabidopsis cDNA clones of GF14 proteins originally were isolated on the basis of their association with the G-box DNA/protein complex by a monoclonal antibody screening approach. GF14 proteins are homologous to the 14-3-3 family of mammalian proteins. Here we demonstrate that recombinant GF14 omega, one member of the Arabidopsis GF14 protein family, is a dimeric protein that possesses many of the attributes of diverse mammalian 14-3-3 homologues. GF14 omega activates rat brain tryptophan hydroxylase and protein kinase C in a manner similar to the bovine 14-3-3 protein. It also activates exoenzyme S of Pseudomonas aeruginosa as does bovine brain factor activating exoenzyme S (FAS), which is itself a member of 14-3-3 proteins. In addition, GF14 omega binds calcium, as does the human 14-3-3 homologue reported to be a phospholipase A2. These results indicate that a single isoform of this plant protein family can have multiple functions and that individual GF14 isoforms may have multiple roles in mediating signal transductions in plants. However, GF14 omega does not regulate growth in an in vivo test for functional similarity to the yeast 14-3-3 homologue, BMH1. Thus, while a single plant GF14 isoform can exhibit many of the biochemical attributes of diverse mammalian 14-3-3 homologues, open questions remain regarding the physiological functions of GF14/14-3-3 proteins.

14-3-3 Proteins↗
PubMed1994

Evolutionary implications of the family of 14-3-3 brain protein homologs in Arabidopsis thaliana.

The GF14 family of proteins in Arabidopsis thaliana consists of a homologous group of polypeptides ranging in size from approximately 27 kDa to approximately 32 kDa. As a group, GF14 proteins are also homologous to a family of mammalian proteins most commonly referred to as 14-3-3 proteins. Several distinct and different biochemical activities have been historically attributed to the various isoforms of the mammalian 14-3-3 proteins. These data present the possibility that the various activities are performed by functionally distinct lineages of the gene family. Here we present phylogenetic analyses based on the derived amino acid sequences of five GF14 isoforms expressed in Arabidopsis suspension-cultured cells. A high degree of sequence integrity is apparent in the various Arabidopsis isoforms, and the overall structures of the plant forms are quite conserved with regard to the structures of the known mammalian forms. These gene phylogenies indicate no evolutionary conservation of specific isoform lineages within both plants and animals. Rather, the evolutionary history of this protein appears to be characterized by a separate radiation of plant and animal forms from a common ancestral sequence. Even though the plant and animal forms have evolved independently since that ancestral split, large domains are conserved in both major lineages.

14-3-3 Proteins↗
PubMed1994

Humans anesthetized with sevoflurane or isoflurane have similar arrhythmic response to epinephrine.

BACKGROUND: Anesthetics can alter the dose of exogenously administered epinephrine that causes cardiac arrhythmias. The purpose of this study was to test the hypothesis that in humans anesthetized with sevoflurane, the arrhythmic response to epinephrine is not different from the response in humans anesthetized with isoflurane. METHODS: We determined the arrhythmogenicity of submucosally administered epinephrine in 40 ASA physical status 1 or 2 patients who were to undergo transsphenoidal surgery. Patients were assigned randomly to be given 1.0-1.3 minimum alveolar concentration sevoflurane or isoflurane. A surgeon, blinded to the anesthetic and the concentration of epinephrine, injected into the nasal submucosa epinephrine 10, 13.3, or 20 micrograms/ml in saline of volume sufficient for surgical need. We defined a "positive" response as three or more premature ventricular contractions within 5 min after initiation of injection. Responses between anesthetic groups within each dose range of epinephrine were compared by chi-squared analysis. RESULTS: No patient given either anesthetic developed premature ventricular contractions with doses of epinephrine less than 5 micrograms/kg. At larger doses of epinephrine (5-9.9 and 10-14.9 micrograms/kg), the frequency of arrhythmias did not differ between patients given sevoflurane and patients given isoflurane. Patients anesthetized with 1.2 minimum alveolar concentration sevoflurane had blood pressure similar to and heart rate less than those of patients anesthetized with similar concentrations of isoflurane. Blood pressure and heart rate were increased similarly in both groups after laryngoscopy and tracheal intubation and after epinephrine injection. CONCLUSIONS: Sevoflurane and isoflurane do not differ in their sensitization of the human myocardium to the arrhythmogenic effect of exogenously administered epinephrine.

Adult↗
PubMed1994

Phosphorylation and calcium binding properties of an Arabidopsis GF14 brain protein homolog.

Arabidopsis GF14 omega was originally described because of its apparent association with a DNA-protein complex; it is a member of the 14-3-3 kinase regulatory protein family that is conserved throughout eukaryotes. Here, we demonstrated that recombinant GF14 omega is expressed in Escherichia coli as a dimer. Blot binding and electrophoretic mobility shift analyses indicated that GF14 omega binds calcium. Equilibrium dialysis further demonstrated that GF14 omega binds an equimolar amount of calcium with an apparent binding constant of 5.5 x 10(4) M-1 under physiological conditions. The C-terminal domain, which contains a potential EF hand motif, is responsible for the calcium binding. The C-terminal domain also cross-reacted with the anti-GF14 omega monoclonal antibody. In addition, GF14 omega is phosphorylated by Arabidopsis protein kinase activity at a serine residue(s) in vitro. Therefore, GF14 omega protein has biochemical properties consistent with potential signaling roles in plants. The presence of a potential EF hand-like motif in the highly conserved C terminus of 14-3-3 proteins together with the calcium-dependent multiple functions attributed to the 14-3-3 proteins indicate that the C terminus EF hand is a common functional element of this family of proteins.

Amino Acid Sequence↗
PubMed1994

Isolation of ribonucleotide reductase from Mycobacterium tuberculosis and cloning, expression, and purification of the large subunit.

Ribonucleotide reductase, an allosterically regulated, cell cycle-dependent enzyme catalyzing a unique step in the synthesis of DNA, the reduction of 2'-ribonucleotides to 2'-deoxyribonucleotides, was purified 500-fold from Mycobacterium tuberculosis Erdman strain through cell disruption, ammonium sulfate fractionation, and dATP-Sepharose affinity column chromatography. As in eucaryotes and certain bacteria and viruses, the M. tuberculosis enzyme consists of two nonidentical subunits, R1 and R2, both of which are required for activity. R1 has a molecular mass of 84 kDa, as identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and photoaffinity labeling with dATP. The amino acid sequences of the N-terminal peptide and two internal peptides were determined, and a partial R1 gene was isolated by PCR with primers designed from these amino acid sequences. Additional coding sequences were isolated by screening size-selected libraries, and a full-length form of M. tuberculosis R1 was generated by PCR amplification of high-molecular-weight M. tuberculosis DNA and expressed in Eschericnia coli. This coding sequence is 2,169 nucleotides long and contains no introns. The predicted molecular mass of R1 from the DNA sequence is 82,244 Da. Recombinant M. tuberculosis R1, purified to homogeneity, was biochemically active when assayed with extracts of M. tuberculosis enriched for R2.

Adenosine Triphosphate↗