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Biomedical subjects

F Li

Publications and source records attributed to F Li.

At least 37 records · Page 2Linked to original sources
PubMed1995

Hyperglycosylation of eosinophil ribonucleases in a promyelocytic leukemia cell line and in differentiated peripheral blood progenitor cells.

We evaluated two independent models of eosinophil differentiation for their ability to synthesize the ribonuclease toxins eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP). Cells from the clone 15 subline of HL-60 (human promyelocytic leukemia) produced both EDN and ECP; production of EDN increased in response to butyric acid (BA). CD34+ peripheral blood progenitor cells (PBPCs) grown with cytokines promoting eosinophil differentiation also produced EDN. EDN from both the clone 15 and PBPCs was more heterogeneous and heavily glycosylated (approximately 22-45 kDa) than EDN from the mature peripheral blood eosinophils (18-25 kDa). The heterogeneity of EDN from the clone 15 cells was not altered by endoglycosidase Hf, whereas treatment with peptide-N-glycosidase F (PNGase F) produced a single-band immunoreactive band (approximately 15 kDa). In contrast, only the highest molecular weight forms of EDN from differentiated PBPCs were eliminated by PNTGase F (reduced to 22-35 kDa), suggesting the presence of uncharacteristic forms of posttranslational modification. Synthesis of hyperglycosylated proteins has not been previously reported in PBPCs and is a feature shared with tumor cells and cell lines.

Butyrates↗
PubMed1995

Double-echo three-point-Dixon method for fat suppression MRI.

A double-echo two-excitation pulse sequence encoding fat and water signals for a phase-sensitive three-point Dixon-type analysis (DE-3PD) was developed and implemented on a 1.5 T MR imager. Data processing was performed using a previously developed two-dimensional (2D) region-growing algorithm, adapted to use double-echo data. Density-, T1-, and T2-weighted fat suppression images were obtained from six volunteers using the new fat suppression method. The images were compared with corresponding images obtained using frequency-selective excitation fat suppression (FATSAT) and a single-echo three-point-Dixon method (SE-3PD). The results demonstrate that the DE-3PD sequence shortens the imaging time by one-third compared with the SE-3PD method, without loss in image quality. The data also show that a 2D region-growing algorithm effectively unwraps the phase of DE-3PD data sets, and that results of DE-3PD fat signal suppression are consistently better than those obtained using a standard FATSAT method. The authors conclude that the double-echo sequence provides density-, T1-, and T2-weighted images that appear to be promising for routine clinical applications.

Abdomen↗
PubMed1995

The clinical application of human bone matrix gelatin.

This paper reports the results of 24 cases of bone defect resulting from bone tumor or tumor condition excision, and of posterior spinal fusion, treated by human bone matrix gelatin. The success rate of bone defect repair and spinal fusion is 91.67%. The results suggest that human bone matrix gelatin has excellent osteoinductive effect and is ideal substitute for bone autografts.

Adolescent↗
PubMed1995

Accelerated stability studies on 16-methylene-17 alpha-acetoxy-19-nor-pregn- 4-ene-3,20-dione (Nestorone).

The stability of the contraceptive steroid, Nestorone (16-methylene-17 alpha-acetoxy-19-nor-pregn-4-ene-3,20-dione) in the solid state and in aqueous solutions, was investigated using reverse-phase high-performance liquid chromatography. In the solid state, whether as a powder or when it is incorporated into Silastic implants, the steroid does not undergo detectable degradation even under severe experimental conditions. In solution, the drug undergoes slow degradation that is dependent on temperature and pH of the medium. The decomposition is defined by first-order mechanism. As expected, the reaction rate increases with increasing storage temperature. The linearity of the Arrhenius plot indicates that there is no change in the reaction mechanism within the temperature range studied. In alkaline media, the drug degrades at a faster rate through hydrolytic rather than an oxidative mechanism. The major hydrolytic degradation product, 16-methylene-17 alpha-hydroxy-19-nor-pregn-4-ene-3,20-dione, was separated and identified by mass spectrometry.

Contraceptive Agents, Female↗
PubMed1995

P-selectin glycoprotein ligand-1 mediates rolling of human neutrophils on P-selectin.

Neutrophils roll on P-selectin expressed by activated platelets or endothelial cells under the shear stresses in the microcirculation. P-selectin glycoprotein ligand-1 (PSGL-1) is a high affinity ligand for P-selectin on myeloid cells. However, it has not been demonstrated that PSGL-1 contributes to the rolling of neutrophils on P-selectin. We developed two IgG mAbs, PL1 and PL2, that appear to recognize protein-dependent epitopes on human PSGL-1. The mAbs bound to PSGL-1 on all leukocytes as well as on heterologous cells transfected with PSGL-1 cDNA. PL1, but not PL2, blocked binding of 125-I-PSGL-1 to immobilized P-selectin, binding of fluid-phase P-selectin to myeloid and lymphoid leukocytes, adhesion of neutrophils to immobilized P-selectin under static conditions, and rolling of neutrophils on P-selectin-expressing CHO cells under a range of shear stresses. PSGL-1 was localized to microvilli on neutrophils, a topography that may facilitate its adhesive function. These data indicate that (a) PSGL-1 accounts for the high affinity binding sites for P-selectin on leukocytes, and (b) PSGL-1 must interact with P-selectin in order for neutrophils to roll on P-selectin at physiological shear stresses.

Amino Acid Sequence↗
PubMed1995

Correlation of expression of transcription factor C/EBP alpha and surfactant protein genes in lung cells.

C/EBP alpha is a transcription factor which can stimulate expression of genes in lipid-metabolizing epithelial cells. We have detected an increase in mRNA for C/EBP alpha in lungs of fetal rats between days 18 and 20 of gestation, correlating with events occurring during the maturation of the surfactant system, such as an increase in the amount of surfactant protein A mRNA. We have found that C/EBP alpha mRNA levels are substantially enriched in type II alveolar epithelial cells purified from adult lung and that the C/EBP alpha protein is present in type II cell nuclei. When the type II cells are removed from the lung and purified, the protein is rapidly lost. However, both surfactant protein gene expression and C/EBP alpha reappear when cells are plated on Matrigel. Levels of C/EBP alpha mRNA from purified cells decline much more slowly than the protein and are still detectable 48 h after cells have been plated on standard tissue culture plastic. We have also detected the C/EBP alpha protein in nuclear extracts of NCI-H441, a lung-derived cell line that expresses surfactant proteins A and B, but not in A549, a lung-derived cell line which does not express the surfactant proteins. Our data suggest that C/EBP alpha is involved in the development and maintenance of the surfactant system in lung type II cells.

Animals↗
PubMed1995

Sequence of rat surfactant protein A gene and functional mapping of its upstream region.

Surfactant protein A (SP-A) is the major pulmonary surfactant protein. We have isolated a rat SP-A genomic clone and determined the sequence from 2.9 kilobases upstream of the transcriptional start through the termination of translation. The exon-intron structure of the rat gene has been determined and compared with the mouse, rabbit, and human genes. We have localized the major transcriptional start site in adult rat lung to nucleotide 30 downstream from the start of the TATA box. Functional mapping indicates that a DNA fragment containing 163 nucleotides upstream of the transcriptional start (-163) can function as a promoter of transcription of a reporter gene in both lung and nonlung derived cell lines. However, the function of this element is weaker in cells of nonlung origin. DNA elements located between -2902 and -163 silence the promoter activity in both lung and nonlung cells. Because the SP-A gene promoter region exhibits limited tissue specificity, the results suggest the existence of other DNA elements which overcome the silencer and confer further lung specificity.

Amino Acid Sequence↗
PubMed1995

Mapping of human inter-alpha-trypsin inhibitor family heavy chain-related protein gene (ITIHL1) to human chromosome 3p21-->p14.

Inter-alpha-trypsin inhibitor family heavy chain-related protein (IHRP) is a novel glycoprotein isolated from human plasma. The cDNA encoding IHRP has recently been cloned from human liver cDNA libraries. We report the mapping of this gene (ITIHL1) by fluorescence in situ hybridization using a 2.5-kb cDNA fragment as a probe. ITIHL1 was localized to chromosome region 3p21-->p14 where the genes of heavy chain 1 and 3 of inter-alpha-trypsin inhibitor are located. This result, together with significant homology between the nucleotide sequences of ITIHL1 and the heavy chain genes, supports ITIHL1 as being a member of an evolutionary related gene family of ITI heavy chains. Northern blot analysis indicated that IHRP was predominantly synthesized in liver. From Southern blot analysis, it was tentatively concluded that ITIHL1 is a single copy gene.

Blood Proteins↗
PubMed1995

[Study on the relationship between uterine bleeding with intrauterine device and viral infection].

OBJECTIVE: To study the relationship between uterine bleeding with intrauterine device (IUD) and virus infection. METHODS: Virus isolation from endometrium samples both with IUD and without IUD was performed with rabbit kidney cell. The cell pathogen effect (CPE) directed the positive isolation. All isolated viruses were further identified by polymerase chain reaction (PCR) for human cytomegalovirus (HCMV) and by neutralizing test for herpes simplex virus type II (HSV-II). RESULTS: The endometrial samples were obtained from four groups: 113 patients with uterine bleeding with IUD; 109 healthy women, without uterine bleeding with IUD; 24 healthy women without IUD and 11 patients with uterine bleeding without IUD. The rates of virus isolation in four groups mentioned above were 59.29%, 19.27%, 16.67% and 63.64% respectively. The positive rates for HCMV and HSV-II in the four groups were 38.81%, 19.05%, 1/4, 3/7 and 23.88%, 23.87%, 1/4, 0.00% respectively. The unidentified viruses were 37.31%, 57.14%, 2/4 and 4/7 respectively. CONCLUSIONS: These results showed that some endometrial samples from both the bleeding groups and the controls were infected by HCMV and HSV-II. The incidence of virus infection in women with uterine bleeding with IUD was much higher than that of the controls, but similar to that is the patients with uterine bleeding without IUD. The results suggested that IUD could activate latent viruses (HCMV, HSV-II) infection and induce bleeding in certain conditions.

Adult↗
PubMed1995

[Surgical treatment of avascular necrosis of the femoral head].

71 patients (83 hips) with avascular necrosis of the femoral head were followed up. The patients had bilateral necrosis (12), and unilateral (59). Their ages ranged from 19 to 71 years. Ficat classification showed stage I for 1 hip, stage II 19 hips, stage III 35 hips, and stage IV hips. According to the severity, the range of motion, the age, and the X-ray appearances, 6 kinds of procedures were used including decompression with bone grafting (32 hips), surface arthroplasty with cartilage (4), surface arthroplasty with fascia (4), replacement of femoral head (7), THA (20), and obturator neuroetomy (16). The follow-up period ranged from 2 years and 3 months to 10 years and 5 months. Postoperative improvement included pain (39.7%), range of motion (21.7%), and walking (33.7%). Among the procedures, decompression with bone grafting showed best results. Treatment revealed better results in stage I, II than in stage III, IV. We emphysize the early diagnosis and management, and choice of procedure should base on the clinical classification.

Adult↗
PubMed1995

[Clinical analysis of 20 cases of idiopathic interstitial pulmonary fibrosis].

This paper describes 20 cases of idiopathic diffuse interstitial pulmonary fibrosis. The clinical manifestations are dry cough, chronic progressive dyspnea, clubbed fingers and velcros rales. CT (HRCT) scanning were performed in 8 patients and the results were compared with the common X-ray chest films, the images of HRCT were more clearer than common chest films, the fine grain shadows, which can not be shown on the common X-ray chest films, were shown on HRCT. The final diagnosis is based on the transbronchial lung biopsy or open lung biopsy.

Adult↗
PubMed1995

[Surveillance of diarrhea in children aged under five in Youxian county, Hunan].

Surveillance analysis of cases with diarrhea in children aged under five years, who visited and were treated at village clinics in rural areas of Youxian County during June 1992 to May 1993, was conducted. Children aged below five under surveillance averaged 1 346, and 223 cases of diarrhea were reported, with a reported incidence of 0.17 per person-year. Incidence was higher in 6-month and one-year groups with a peak during May to August. But no sex difference of diarrhea incidence existed. Use of oral rehydration solution (ORS) accounted for 87.89% of the cases, with an average of 1.56 packages (each package containing 500 ml) per case, and 95.52% of dehydrated cases used ORS, with average of 2.02 packages per case. Use of intravenous rehydration account for 1.79% of the cases, 58.74% of them used antibiotics and 16.03% of them used more than two kinds of antibiotics, and 47.98% of the cases used both ORS and antibiotics. Occurrence of blood, mucus and pus in stool accounted for 12.64% of the total cases. All indices of surveillance in 1993 improved, compared with those in September 1991.

Child, Preschool↗
PubMed1995

[Effects of hypoxia on the expression of platelet-derived growth factor (PDGF) gene and PDGF-B chain protein in porcine pulmonary artery endothelial cells].

Northern blot, slot blot hybridization and quantitative immunocytochemistry analyses were used to study the effects of hypoxia on the expression of PDGF gene and PDGF-B chain protein in cultured pulmonary artery endothelial cells (PAEC). Hypoxia (3% oxygen) significantly increased PDGF-B chain mRNA in PAEC, whereas mRNA level of PDGF-A chain was not increased significantly in comparison with normoxic control (21% oxygen). PDGF-B chain immunoreactivity on PAEC exposed to hypoxia was markedly stronger than that of normoxic PAEC and PDGF-B China immunoreaction. was found in cytoplasm and perinuclear region of the hypoxic PAEC, however, only in the nuclear region of normoxic PAEC. Increased expression of PDGF-B chain protein roughly paralleling that of PDGF-B mRNA was also observed. These results suggest that hypoxia may stimulate the expression of PDGF-B chain by PAEC in vivo and PDGF may play an important role in the vascular remodeling of hypoxic pulmonary hypertension.

Animals↗
PubMed1995

[Congenital pulmonary lymphangiectasis].

Six rare cases of congenital pulmonary lymphangiectasis were presented. The macroscopic characteristic of the lungs was honeycomb appearance due to extreme dilatation of the lymphatic spaces in the subpleural, interlobular, peribronchial and perivascular connective tissue. They had thin walls lined by endothelium. The dilated lymphatics may be due to congenital developmental defects or obstruction of major lymphatics, but they appeared to be associated only with pulmonary venous hypertension.

Female↗
PubMed1995

Endolymphatic stromal myosis of the uterus. Clinicopathological analysis of five cases.

Five cases of endolymphatic stromal myosis (ELSM) were studied using histological, histochemical and immunohistochemical methods. ELSM is a well-differentiated tumor resembling the normal endometrial stoma, with a low mitotic activity. So ELSM is considered as a kind of potentially malignant tumor different from endometrial stomal sarcoma and benign stromal nodules as well, though it can metastasize to the outside of uterus. ELSM may be derived from the stem cells that are normally present in the stroma of uterus, and can manifest multidifferentiation.

Adult↗
PubMed1995

Functional effects of mutations in the putative agonist binding region of recombinant alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors.

Structural correlates of ligand binding to alpha-amino-3-hydroxy-5-methyl- 4-isoxazolepropionic acid (AMPA) receptors were examined by altering conserved lysine residues to either glutamate or glutamate at position 445 of the GluR-A subunit and position 449 of the GluR-B subunit. Receptors were expressed in human embryonic kidney 293 cells and in Xenopus oocytes as homomeric GluR-A or heteromeric combinations of GluR-A/B. The functional properties of the resulting receptors were measured with patch-clamp and voltage-clamp electrophysiology. These mutations, which reduced the total positive charge at the lysine 445 position, selectively altered the affinity of some ligands and had no obvious effect on receptor desensitization properties. The L-glutamate EC50 was 10.2 microM when wild-type GluR-A was coexpressed with GluR-B (GluR-A/B) and 38.9 microM when GluR-A445Q/B449Q receptors were tested. The AMPA EC50 was similarly reduced (wild-type, 3.71 microM; GluR-A445Q/B449Q, 21.4 microM). Receptors containing a glutamate residue at this position were even less sensitive to L-glutamate and AMPA. Whereas the apparent potency of L-glutamate varied inversely with the total positive charge regardless of the subunit, the affinity of AMPA was more sensitive to mutations in GluR-A than to those in GluR-B. Interestingly, the EC50 of kainate was unaffected by most of these mutations and actually increased slightly with GluR-A445E/B449E receptors. The affinity of 6-cyano-2,3-dihydroxy-7- nitroquinoxaline (CNQX) was slightly reduced with GluR-A445E/B449E receptors, whereas the apparent affinity of GYKI52466 was unchanged. These data confirm that structural correlates of binding to AMPA receptors vary among different ligands.

Animals↗
PubMed1995

Pathogenicity: animal models.

Animal models offer the opportunity to study the interaction of the virus and the host and to unravel the mechanism in processes such as persistence of the virus and virus-induced pathology. Primary infection results in a generalized infection as shown by the presence of virus in many organs. During viraemia the virus is present in mononuclear cells by which it is transported through the body. In neonates and in immuno-suppressed animals the infection results in multiorgan failure, leading to death. Recent data have shown that infection of endothelial cells in the microvasculature and mononuclear cells seems to be important in the pathogenesis of cytomegalovirus (CMV)-induced disease. After primary infection the virus persists in the body. Although the exact localization of the latent virus is unknown it is clear that during latency viral DNA is present in many organs. By immune suppression the virus can reactivate from its latent state. In addition to the direct complications attributable to the virus itself, CMV has modulating effects on the immune response. Although in some instances the infection leads to immune suppression, the virus infection can also accelerate inflammatory and immune responses. Studies in mice have shown that CMV infection can exacerbate graft-versus-host reactions, and experiments in rats using allogeneic transplants indicate that CMV infection results in enhanced chronic rejection in which acceleration of the immune response is involved. Although the exact mechanism is not clear, recent data indicate that cytokines, such as tumor necrosis factor alpha are involved in these processes.

Acute Disease↗