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Biomedical subjects

J Lin

Publications and source records attributed to J Lin.

At least 397 records · Page 22Linked to original sources
PubMed1997

[Molecular cloning of the imipenem resistant gene in bacteroides fragilis].

Imipenem, as a representative of-cabapenem, is one of the most effective beta-Lactam agents against Bacteroides, but recently there have been a few reports on the resistant strains of Bacteroides. To explore the mechanism of imipenem resistance (IMPr) at the molecular level, we extracted chromosome DNA of the resistant strains and acquired a 1.7 kb fragment of resistant gene of imipenem. Recombinant plasmid was stably reserved in generation after generation in E. coli DH5. Resistant gene of imipenem was labeled with Dig-11-dUTP by way of random prime, and 40 strains of clinically isolated Bacteroides were detected by the prepared DNA probe. Two IMPr strains showed hybridization signal, whereas 38 IMPr strains did not show such a signal. The result suggests that the Dig-labeled IMPr gene probe can be used in molecular epidemiology for investigating IMPr strains.

Bacteroides fragilis↗
PubMed1997

[Orthodontic treatment in unilateral cleft lip and palate patients with crossbite].

Serious malocclusion is often seen in the cleft lip and palate patients. Orthodontic treatment is very complex and difficult. The aim of this study was to investigate the characteristics of the treatment in this kind of the patients through the clinical treatment of the thirty-two patients. We conclude (1) Many patients need alveolar bone grafting in order to award good arch form and occlusion. (2) It need longer time in expanding of the upper arch and retaining. (3) Main changes after treatment of edgewise appliance took place in dental-alveolar region. (4) 34.3% of the patients need orthognathic surgery to improve their profile. So it indicated that reverse headgear should be used in the early time for the cleft patients to get a good treatment result.

Adolescent↗
PubMed1997

[Clinical and histological findings of retrocorneal membrane after keratoplasty].

PURPOSE: To observe the clinicopathologic changes of retrocorneal membrane after keratoplasty. METHODS: Light microscope and histochemical technique were used. RESULTS: The clinicopathologic review of 108 unsuccessful keratoplasties revealed the presence of 45 retrocorneal membrane, which seems to depend on the wound abnormality, rejection of corneal transplantion, epithelium in growth, hyphema, and iris synechias. CONCLUSION: The retrocorneal membrane derives from the host corneal stromal keratocytes and the metaplasia of corneal endothelial cells and monocytes.

Corneal Diseases↗
PubMed1997

[A research on real-time ventricular QRS classification methods for single-chip-microcomputers].

Ventricular QRS classification is key technique of ventricular arrhythmias detection in single-chip-microcomputer based dynamic electrocardiogram real-time analyser. This paper adopts morphological feature vector including QRS amplitude, interval information to reveal QRS morphology. After studying the distribution of QRS morphology feature vector of MIT/BIH DB ventricular arrhythmia files, we use morphological feature vector cluster to classify multi-morphology QRS. Based on the method, morphological feature parameters changing method which is suitable to catch occasional ventricular arrhythmias is presented. Clinical experiments verify missed ventricular arrhythmia is less than 1% by this method.

Arrhythmias, Cardiac↗
PubMed1997

[The preparing of Bacillus penetrans preparation and their controlling to root-knot nematodes].

In order to make use of B. penetrans the preparation of these bacteria was prepared successfully. Each gram of the specimen contains more than 3.1 x 10(8) spores according to determination by bloodcount plate. The method of its production are: First, infect the larvae of root-knot nematodes with the spores of B. penetrans. Second, inoculate infectable plants with the infected larvae. Third, beat the root-systems of inoculated plants after adding some water. The flowed liquid from a bronze sieve was mixed with the clear water, filtered, precipitated, air-dried under 5-10 degrees C, and grinded into fine powder, When these powder was added into the water which contained the larvae of root-knot nematodes, the spores of B. penetrans adhered to the cuticles of these larvae in 24 h. The pot experiments of tomato, chilli and cockscomb showed that the galls, egg-sacs, females, males and all-stages of larvae produced by the plant inoculated with the larvae infected with B. penetrans are about 75%-80% less than that without these bacteria. Thus it can be seen that the spores of B. penetrans can depress the populations of root-knot nematodes obviously. Therefore, it is a promising preparation for biological control.

English Abstract↗
PubMed1997

Mechanical analysis and treatment of Harrington-rods broken after initial operation for scoliosis.

Twenty-two cases of scoliosis with Harrington-rods broken after operation were treated by rod-sleeve method. The results of follow-up from 1 year and 3 months to 9 years and 3 months showed that all of the patients, but one patient occurred Harrington-rod rebroken and one's fixation being removed because of back pain in 6 months and 5 years and 11 months after rod-sleeve procedure, respectively, had no complaints. The author also found that the rod underwent a decrease in cross-sectional area of approximately 43.7% at the ratchet-shaft junction in experimental study on Harrington-rods, and stress unfairly distribution, stress concentration and cyclic loading producing fatigue in metals were proved to be the main cause of broken by mechanical analysis of Harrington-rod loaded in the body. In concluson, the rod-sleeve procedure was the effective method to keep from Harrington-rods broken.

Adolescent↗
PubMed1997

[Multi-function ECG pre-amplifier for portable monitor].

In this paper, an ECG pre-amplifier portable monitor is given, which has many functions, i.e., 50 Hz notch, lead-off alarm and pacer pulse inhibition. The amplifier only consists of 3 chips of 8 pin ICs, and consumes current less than 1.4 mA.

Electrocardiography, Ambulatory↗
PubMed1997

Characterization of two human flavin-containing monooxygenase (form 3) enzymes expressed in Escherichia coli as maltose binding protein fusions.

To examine the possibility for drug metabolism polymorphism, adult human flavin-containing monooxygenases (form 3) (EC 1.14.13.8) that differ at one amino acid were expressed in Escherichia coli as maltose binding protein fusions. The cDNA that was first reported during the cloning of adult human flavin-containing monooxygenase was designated the wild type lys158 enzyme. A second cDNA has been identified as a common polymorphism in some human populations and was designated the glu158 enzyme. The cDNA that encodes both enzymes was subcloned into a high yield protein fusion expression system, expressed, and the protein was partially purified by affinity chromatography and characterized for enzyme activity with selective functional substrate probes. N- and S-oxygenation activity of both enzymes was determined with 10-(N,N-dimethylaminopentyl)-2-(trifluoromethyl)phenothiazine and methyl p-tolyl sulfide, respectively. It was found that expression of both lys158 and glu158 enzymes of the human flavin-containing monooxygenase form 3 as fusions with the maltose binding protein resulted in an enzyme that was soluble and greatly stabilized and had a reduced requirement for detergent during enzyme purification and during the assay for activity. Expression of the fusion proteins has allowed the preparation of stable and highly active enzyme at greater purity than was readily possible in the past. With the exception of the stability and solubility characteristics, the physical and chemical properties of lys158 and glu158 maltose binding fusion proteins of human flavin-containing monooxygenase form 3 variants resembled that of flavin-containing monooxygenase enzyme activity associated with human liver microsomes and enzyme isolated from a previous Escherichia coli expression system that lacked the protein fusion. Comparison of the catalytic activity of the two fusion proteins showed that while both forms were active, there were differences in their substrate specificities. Expression of the adult human flavin-containing monooxygenase form 3 as a maltose binding protein has allowed considerable advances over the previously reported cDNA-expressed enzyme systems and may provide the basis for examining the role of the flavin-containing monooxygenase in human xenobiotic or drug metabolism.

ATP-Binding Cassette Transporters↗
PubMed1997

Treatment of humeral shaft fractures by retrograde locked nailing.

From 1992 to 1994, 29 middle and 19 distal humeral shaft fractures (39 acute fractures, six nonunions, and three pathologic fractures) in 48 patients were treated by retrograde locked nailing. The first eight acute fractures were treated with Seidel nails, the other 40 fractures with specially designed humeral locked nails. Nails were inserted from the supracondylar (6) or the olecranon fossa (42) entry portal. With a single operation, all acute fractures and nonunions achieved osseous union without serious complications. The average time to union was 8.2 weeks for acute fractures and 14.2 weeks for nonunions. Recovery of shoulder function was complete. Elbow motion was excellent in all but one nonunion that resulted from a Type IIIB open fracture. Two patients with supracondylar entry had apex to posterior angular malunion. One patient with a distal comminuted fracture had varus malunion. Three patients had an iatrogenic bony split, but healing was unaffected. Patients with pathologic fractures maintained satisfactory arm function postoperatively. Given the few complications and good functional recovery seen in this study, retrograde locked nailing appears to be a good alternative treatment in middle and distal humeral shaft fractures. The olecranon fossa approach, with more linearity to the humerus, is preferred. In the authors' experience, humeral locked nails are inserted more easily and are associated with fewer complications than are Seidel nails.

Adolescent↗
PubMed1997

N-oxygenation of phenethylamine to the trans-oxime by adult human liver flavin-containing monooxygenase and retroreduction of phenethylamine hydroxylamine by human liver microsomes.

The biogenic amine phenethylamine has been shown to be N-oxygenated by human flavin-containing monooxygenase (FMO) (form 3) and human liver microsomes and, to a much lesser extent, N-oxygenated by porcine liver FMO1 and porcine liver microsomes but not by rabbit FMO2. Adult human liver microsomes catalyze the NADPH-dependent N-oxygenation of phenethylamine to the corresponding trans-oxime through the intermediacy of phenethyl hydroxylamine. In addition to trans-oxime formation, phenethyl hydroxylamine is retroreduced to phenethylamine in the presence of human or porcine liver microsomes. Studies on the biochemical mechanism of N-oxygenation suggested that trans-oxime formation was dependent on the human FMO (form 3) and that retroreduction was stimulated by superoxide and dependent on a cytochrome P-450 system. These conclusions are based on studies examining the effects of incubation conditions on phenethylamine N-oxygenation and the effect of reactive oxygen species on phenethyl hydroxylamine retroreduction, respectively. The pharmacological activity of synthetic phenethyl hydroxylamine and phenethyl oxime with a number of biogenic amine receptors and transporters was examined in vitro. In all cases examined, the affinity of phenethyl hydroxylamine and the corresponding oxime for a biogenic transporter or receptors was very poor. The results suggest that the biogenic amine phenethylamine is efficiently sequentially N-oxygenated in the presence of human liver microsomes or cDNA-expressed FMO (form 3) to phenethyl hydroxylamine and then to oximes that are pharmacologically inactive and serve to terminate biological activity. N-Oxygenation of phenethylamine to the corresponding trans-oxime is a detoxication process that abrogates pharmacological activity.

Adult↗
PubMed1997

Extractive L-lactic acid fermentation with immobilized Rhizopus oryzae in a three-phase fluidized bed.

The Rhizopus oryzae was immobilized by the calcium alginate entrapment method. A three-phase fluidized-bed bioreactor was designed to perform the immobilized-cell L-lactic acid fermentation. A solvent extraction column was coupled with the bioreactor to remove L-lactic acid from the fermentation broth. The TRPO was selected as solvent and sulfonated kerosene as diluent. The results indicated that the pH value in the broth was regulated above pH 3.5 and the fermentation rate was as high as 11 g L-lactic acid per hour per liter of beads. A mathematical model was proposed to describe the concentration of L-lactic acid in the extractive fermentation.

Fermentation↗
PubMed1997

Studies on efficacy of praziquantel and mebendazole-medicated salt in treatment of Echinochasmus fujianensis infection.

The therapeutic effect of praziquantel and mebendazole-medicated salt has been studied in 109 cases with Echinochasmus fujianensis infection. These cases were randomly divided into four groups: 2 groups with a single dose of praziquantel 5 mg/kg or 2.5 mg/kg; and other 2 groups with mebendazole 800mg or 400 mg in 10d table salt. Four weeks after treatment, the egg negative conversion rates were 100%, 92.3%, 85.2% and 71.4% respectively, the egg reduction rates were 84.8-100%, and side-effects were mild. The symptoms caused by infection such as abdominal pain, diarrhea, distension and anorexia were obviously relieved. These data indicated that praziquantel is the drug of choice in the treatment of Echinochasmus fujianensis. The dosage is only 2.5 mg/kg, and its egg negative conversion rate and reduction rate reach 92.3% and 95.4%, respectively. For convenience, the dosage can be made according to their age. Children under 12 take half a tablet (100 mg), and one tablet (200 mg) for those over 12. This dosage is approximately equal to 2.5-5.0 mg/kg. Although the efficacy of mebendazole is lower than praziquantel, its egg negative conversion rate also reaches 71.4-85%. Mebendazole-medicated salt can be used for treating Echinochasmus fujianensis infection as the presence of co-infection with nematodes.

Adolescent↗
PubMed1997

Research on the mechanism of endothelin inflammatory effects on human mesangial cells.

OBJECTIVE: To investigate the mechanism of endothelin (ET) inflammatory effects on human mesangial cells (HMC). METHODS: The following experiments were performed on cultured HMC after ET-1 stimulation: (1) the expression of tumor necrosis factor-alpha (TNF alpha), interleukin-1 beta (IL-1 beta), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelin-1 (ET-1) itself messenger ribonucleic acid (mRNA) was determined by Northern Blot analysis; (2) the TNF alpha concentration was tested with radioimmunoassay; the IL-1 activity was assayed by the enhancement of thymocyte proliferation in response to mitogen; the surface expression of ICAM-1 and VCAM-1 was measured with cell enzyme linked immunoadsorbent assay (ELISA) analysis. RESULTS: ET-1 (10(-7) mol/L) induced the following changes on HMC: (1) up-regulation of the expression of TNF alpha mRNA and protein; (2) up-regulation of the expression of ICAM-1 and VCAM-1 mRNA and protein; (3) up-regulation of the expression of ET-1 itself mRNA. However, the expression of IL-1 mRNA and protein was not changed. CONCLUSIONS: ET-1 can stimulate HMC to produce TNF alpha, ICAM-1 and VCAM-1, and thereby induce inflammatory effects. ET-1 can also stimulate HMC to up-regulate the expression of ET-1 itself, so as to amplify inflammatory effects. So, ET-1 is actually an inflammatory mediator and may play an important role in the pathogenesis of glomerulonephritis.

Cells, Cultured↗
PubMed1997

[Clinical evaluation on laparoscopic diagnosis of pelvic endometriosis by heat-colour test with endocoagulation].

OBJECTIVE: To assess the value of heat-colour test (HCT) with endocoagulation under laparoscopy as a new method for diagnosis of pelvic endometriosis (EM). METHODS: Laparoscopic visible examination (LVE), lesion biopsy and HCT with endocoagulation were employed for diagnosis of EM in 83 cases of infertility. Brown-black colour changes of peritoneal tissue after endocoagulation with controlled heating (100 C) indicate EM implants (HCT positive). RESULTS: LVE indicated that 35 cases had peritoneal lesions typical of EM in appearance. HCT was positive in all cases of visible EM lesions. 48 cases showed no visible peritoneal lesions by LVE, but nonpigmented peritoneal EM lesions were detected by HCT in 20 of the 48 cases. A variety of gross appearances of nonpigmented EM lesions were found in our study including: peritoneal hyperemia (70.9%), circular peritoneal defects (12.7%), semitransparant glandular excrescences (10.9%), white opacification of the peritoneum (10.9%) and normal appearance (5.4%). 25 biopsies were taken from nonpigmented peritoneal lesions in 13 cases. Histology examinations revealed the presence of EM in 64.0% of them. CONCLUSIONS: HCT is a reliable, sensitive and accurate method for diagnosis of EM. It can overcome multiple factors for missing diagnosis of EM by LVE and biopsy. The clinical significance of HCT is its ability to detect nonpigmented endometriotic lesions, to differentiate the causes of pelvic adhesions, therefore to increase accuracy of FIGO EM staging under laparoscopy.

Endometriosis↗
PubMed1997

[Infective factors of adult secretory otitis media].

There were histories of the upper expiratory tract infection in 49 out of 86 cases in adult secretory otitis media (SOM). Among them, thirty two cases were administrated antibiotics a week ago when the effusions were collected. The patient's Eustachian tubes in twenty nine cases were clinically ventilated. The endotoxins were positive in 39 out of 86 specimen tested with limulus assay, among these specimen, bacteria were cultured from 11 specimen. The data exibited that the appearance of the SOM is related to the existence of the infective factors in the middle ear cavity. The upper expiratory tract infection before the onset of the middle ear effusions is one of the important causes inducing the disease. The lower rate of bacteria culture than that of endotoxins is related with the administration of antibiotics before the onset of the disease. The administration of antibiotics in the treatment of the middle ear effusions will help to elimilate bacteria in the cavity of the middle ear effusions, improve the ventilating function of the Eustachian tube and make the effusions turn to disappearance.

Adolescent↗
PubMed1996

Blockade of multiple costimulatory receptors induces hyporesponsiveness: inhibition of CD2 plus CD28 pathways.

T-lymphocyte activation requires engagement of the T cell receptor with antigen-major histocompatibility complex, and simultaneous ligation of costimulatory pathways via the lymphocyte receptors CD2 and CD28/ CTLA4. Anti-CD2 monoclonal antibody (mAb) blocks the interaction of the antigen-presenting cell receptor CD48 with its ligand CD2, whereas CTLA4Ig binds with high affinity to the antigen-presenting cell ligands B7-1 and B7-2, blocking their interaction with CD28/CTLA4. We tested the immunosuppressive effects of simultaneously blocking both costimulatory pathways. Using donor C57BL/6J (H2b) hearts transplanted to CBA/J (H2k) recipients, anti-CD2 mAb plus CTLA4Ig administered at the time of transplantation prolonged cardiac allograft mean survival time to >120 days compared with untreated controls (12.2+/-0.5 days, P<0.01), anti-CD2 mAb alone (24.8+/-1.0 days, P<0.01), or CTLA4Ig alone (55.0+/-2.0 days, P<0.01). Retransplantation of these recipients with donor-specific and third-party grafts demonstrated that hyporesponsiveness and tolerance were achieved. In vitro stimulation of lymphocytes from tolerant recipients with donor-specific alloantigen resulted in normal cytotoxic T lymphocyte and mixed lymphocyte reaction responses, showing that clonal deletion or anergy did not occur, but that graft adaptation or suppression likely helped to maintain long-term graft survival. In vitro combinations of anti-CD2 mAb and CTLA4Ig suppressed the generation of allogeneic cytotoxic T lymphocytes (58%) and the mixed lymphocyte reaction (36%); CTLA4Ig was more effective in this regard and the two agents were not synergistic. Anti-CD2 mAb and CTLA4Ig suppressed mitogen-driven proliferation in differential fashions, suggesting that they affected independent signaling pathways. Anti-CD2 mAb and CTLA4Ig also inhibited interleukin (IL)-2, IL-4, and IL-2 receptor (CD25). These data indicate that anti-CD2 mAb plus CTLA4Ig induces hyporesponsiveness and tolerance. The mechanism is likely related to the initial disruption of independent pathways of T-lymphocyte activation leading to antigen-specific long-term graft survival.

Abatacept↗