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Biomedical subjects

L Kong

Publications and source records attributed to L Kong.

At least 19 recordsLinked to original sources
PubMed2006

Overexpression of phosphatase of regenerating liver-3 in breast cancer: association with a poor clinical outcome.

BACKGROUND: Increasing evidence has suggested that phosphatase of regenerating liver-3 (PRL-3) plays an important role in cancer cell migration, invasion and metastasis. However, the correlation between the PRL-3 expression and clinical outcome in breast cancer has not been investigated. PATIENTS AND METHODS: Using a PRL-3-specific monoclonal antibody 3B6, PRL-3 expression was assessed by immunohistochemistry in tumor tissues from 382 breast cancer patients with a median follow-up of 65 months. RESULTS: We found that 34.8% patients expressed a high level of PRL-3 protein in their tumors. Patients with a high level of PRL-3 in the tumor had a worse disease-specific survival (DSS) rate than those with a low level of PRL-3 (74.0% versus 84.9%, P = 0.011), and PRL-3 remained an independent prognostic marker for DSS (HR 1.8, 95% CI 1.1-2.9, P = 0.019) in multivariate analysis. More importantly, in 219 node-negative patients, PRL-3 showed a significant correlation with DSS in univariate analysis (P = 0.014) and retained a borderline significance (HR 2.65, 95% CI 0.92-7.64, P = 0.071) in multivariate analysis. CONCLUSIONS: Our results suggest that PRL-3 may serve as an unfavorable prognostic marker in breast cancer, especially for patients with node-negative diseases. Thus, our findings may provide useful information for individualized therapy in the clinical setting.

Adult↗
PubMed2006

Design of vaccine equivalence/non-inferiority trials with correlated multiple binomial endpoints.

Immunogenicity trials that study the immune responses to vaccination are often used in the vaccine development process as alternatives to clinical efficacy trials. The comparisons of immune responses among various treatment groups are conducted in a non-inferiority or equivalence framework. When there exists a level of immune response that correlates with protection against disease, it is of interest to compare the proportion of responders as defined as response above a specific level or as a predefined increase in immune levels for post-vaccination levels above pre-vaccination levels. Since vaccines often contain several antigens, the correlations between the immune responses need to be taken into account in the analysis. In this paper, we describe appropriate testing methods for demonstrating the non-inferioritylequivalence of two treatments on each of the binomial endpoints. We conduct a comprehensive simulation study to shed light on how the Type I error and power are affected and to what extent when correlated multiple binomial endpoints are present in the vaccine trials. We also illustrate the computation of power for assessment of non-inferioritylequivalence in real studies.

Adolescent↗
PubMed2005

DNA markers associated with low Fusarium head blight incidence and narrow flower opening in wheat.

Fusarium head blight (FHB) of wheat, caused by Fusarium graminearum, is an important fungal disease in many wheat-growing areas of the world. The objectives of this study were to determine the relationship between width and duration of flower opening and incidence of FHB in wheat, and to identify DNA markers associated with narrow flower opening and low FHB incidence. It was hypothesized that wheat lines whose flowers open briefly and narrowly have a reduced risk of infection. To test the hypothesis, we crossed wheat cultivars Patterson and Goldfield to generate a population of 100 random F(2)-derived recombinant inbred lines (RILs). Florets of Patterson open wide; florets of Goldfield tend to stay closed. The population of RILs was characterized for FHB incidence and flower opening width (FOW) and duration in the F(7:9) and F(7:10) generations. Of the 305 simple sequence repeat primer pairs screened on the parents, 79 amplified polymorphic DNA bands. Pooled DNA from each of the two bulks was tested with these 79 SSR primer pairs. Four markers were found to have significant marker-trait association with low FHB incidence and narrow flower opening. The major QTL effect associated with narrow flower opening and low FHB incidence was found between the map interval Xbarc200-Xgwm210, explaining 29% of the phenotypic variation for FHB incidence averaged over six replicated tests in Indiana in 2002 and 2003. This adds credence to the hypothesis that narrow flower opening is responsible for low FHB incidence in this population. Breeding wheat lines for both morphological avoidance, such as narrow flower opening, and physiological resistance to FHB may be valuable in future breeding research to reduce crop production and grain quality losses in wheat due to FHB.

Crosses, Genetic↗
PubMed2005

Two cis-acting elements in negative RNA strand of Hepatitis C virus involved in synthesis of positive RNA strand in vitro.

Sequences at the 3'-ends of both positive and negative strands of Hepatitis C virus (HCV) RNA harbor cis-acting elements required for RNA replication. However, little is known about the properties of the negative RNA strand as a template for the synthesis of positive RNA strand. In this study, a purified recombinant HCV RNA-dependent RNA polymerase (RdRp) was used to investigate the synthesis of positive RNA strand using the 3'-terminal region of negative RNA strand ((-)3'T RNA) as template. A mutagenesis analysis was performed to evaluate the role of the 3'-proximal stem-loop and the first 3'-cytidylate (3'C) of the negative RNA strand in the synthesis of the positive RNA strand. A negative RNA strand of wild type (wt) HCV as template was able to direct the synthesis of a full-length positive RNA strand. Deletion of the 3'-proximal stem-loop resulted in an approximately 90% decrease in RNA synthesis. Disruption of the 3'-proximal stem-loop structure by nucleotide substitutions led to a 70-80% decrease in RNA synthesis. However, the restoration of the stem-loop by compensatory mutations in the stem region restored also the RNA synthesis. Likewise, the deletion or substitution of the first 3'C by guanylate (G) led to a 90% decrease in the RNA synthesis; while the substitution by adenylate (A) or uridylate (U) resulted in a 60-80% decrease in the RNA synthesis only. These findings demonstrate that the 3'-proximal stem-loop and the first 3'C of the negative RNA strand of HCV are two cis-acting elements involved in the synthesis of the positive RNA strand.

3' Untranslated Regions↗
PubMed2001

Analysis of terpene compounds in Cimicifuga foetida L. by reversed-phase high-performance liquid chromatography with evaporative light scattering detection.

An RP-HPLC method with evaporative light scattering detection (ELSD) was developed for the analysis of terpene compounds in traditional Chinese medicine. Actein, 27-deoxyactein and cimicifugoside in a typical Chinese medicine of Cimicifuga foetida L. were quantitatively analyzed. Comparing ELSD with UV detection under the same eluent conditions, the former showed better sensitivity and a more stable baseline. The ELSD responses versus sample size of three terpenes and those in double logarithmic were investigated. The good calibration curves in double logarithmic coordinator for actein, 27-deoxyactein and cimicifugoside were obtained. Three solutions for the extraction of the terpene compounds were also compared, the results indicated that methanol-water (80:20) is the best among them. The method was applied to quantify actein, 27-deoxyactein and cimicifugoside in Cimicifuga foetida L. from Hunan, China. It was shown that ELSD is an effective detection method for the analysis of the non-volatile terpenes in traditional Chinese medicine.

Calibration↗
PubMed2001

Chromatographic separation of proteins on metal immobilized iminodiacetic acid-bound molded monolithic rods of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate).

Continuous rod of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate) was prepared by a free radical polymerization within the confines of a stainless-steel column. The epoxide groups of the rod were modified by a reaction with iminodiacetic acid (IDA) that affords the active site to form metal IDA chelates used for immobilized metal affinity chromatography (IMAC). The efficiency of coupling of IDA to the epoxide-contained matrix was studied as a function of reaction time and temperature. High-performance separation of proteins, based on immobilized different metals on the column, were described. The influence of pH on the adsorption capacity of bovine serum albumin on the Cu2+-IDA continuous rod column was investigated in the range from 5.0 to 9.0. Purification of lysozyme from egg white and human serum albumin (HSA) on the commercially available HSA solution were performed on the naked IDA and Cu2+-IDA continuous rod columns, respectively; and the purity of the obtained fractions was detected by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry.

Chromatography, Affinity↗
PubMed2001

Arundifungin, a novel antifungal compound produced by fungi: biological activity and taxonomy of the producing organisms.

Echinocandins, the lipopeptide class of glucan synthase inhibitors, are an alternative to ergosterol-synthesis inhibitors to treat candidiasis and aspergillosis. Their oral absorption, however, is low and they can only be used parenterally. During a natural product screening program for novel types of glucan synthesis inhibitors with improved bioavailability, a fungal extract was found that inhibited the growth of both a wild-type Saccharomyces cerevisiae strain and the null mutant of the FKS1 gene (fks1::HIS). The mutant strain was more sensitive to growth inhibition, suggesting that the fungal extract could contain an inhibitor of glucan synthesis. A novel acidic steroid, named arundifungin, was purified from a fungal extract obtained from a liquid culture of Arthrinium arundinis collected in Costa Rica. Arundifungin caused the same pattern of hallmark morphological alterations in Aspergillus fumigatus hyphae as echinocandins, further supporting the idea that arundifungin belongs to a new class of glucan synthesis inhibitors. Moreover, its antifungal spectrum was comparable to those of echinocandins and papulacandins, preferentially inhibiting the growth of Candida and Aspergillus strains, with very poor activity against Cryptococcus. Arundifungin was also detected in nine other fungal isolates which were ecologically and taxonomically unrelated, as assessed by sequencing of the ITS1 region. Further, it was also found in two more Arthrinium spp from tropical and temperate regions, in five psychrotolerant conspecific isolates collected on Macquarie Island (South Pacific) and belonging to the Leotiales, and in two endophytes collected in central Spain (a sterile fungus belonging to the Leotiales and an undetermined coelomycete).

Antifungal Agents↗
PubMed2001

Dysphagia caused by a fetus-in-fetu in a 27-year-old man.

Mechanical obstruction of the distal esophagus by a fetus-in-fetu is an extremely rare condition that has not been previously reported. We present the case of a 27-year-old man who presented with dysphagia caused by fetus-in-fetu contained within a retroperitoneal cystic cavity. The tumor, noticed since childhood, did not cause any symptoms until a year before presentation when symptoms of dysphagia developed. We propose including this entity in the differential diagnosis of a retroperitoneal mass.

Adult↗
PubMed2001

TGF-beta1 null mutation leads to CD154 upregulated expression in affected tissues.

The TGF-beta1(-/-) mouse is a murine model for systemic autoimmune disease. The aim of this study is to elucidate the immunological mechanism that leads to multifocal tissue inflammation and autoantibody production in TGF-beta1(-/-) mice. Heart, lung, liver, and salivary gland from TGF-beta1(-/-) were assessed for CD154 expression by RT-PCR and immunohistochemistry. Compared to wild-type littermates, CD154 expression was elevated in all tissues studied. Furthermore, IL-12 mRNA was expressed in the salivary gland and heart of TGF-beta1(-/-) mice and not in wild-type littermates. This suggests that the CD154 pathway is activated in these tissues. This shows that TGF-beta1 regulates CD154 expression leading to spontaneous IL-12 production and autoimmunity.

Animals↗
PubMed2001

Antimicrobial activity of ergokonin A from Trichoderma longibrachiatum.

AIMS: Natural fungal products were screened for antifungal compounds. The mode of action of one of the hits found and the taxonomy of the producing organism were analysed. METHODS AND RESULTS: An extract from a Trichoderma species showed a more potent activity in an agar-based assay against the null mutant fks1::HIS strain than against the wild-type strain, suggesting that it could contain a glucan synthesis inhibitor. The active component was identified as the known compound ergokonin A. The compound exhibited activity against Candida and Aspergillus species, but was inactive against Cryptococcus species. It induced alterations in the hyphal morphology of Aspergillus fumigatus. The identification of the producing isolate was confirmed by sequencing of the rDNA internal transcribed spacers and comparison with the sequences of other Trichoderma species. The analysis showed that the producing fungus had a high homology with other strains classified as Trichoderma longibrachiatum and its teleomorph Hypocrea schweinitzii. CONCLUSIONS: The antifungal activity spectrum of ergokonin A and the morphology alterations induced on A. fumigatus are consistent with glucan synthesis as the target for ergokonin A. The production of ergokonin A is not uncommon, but is probably restricted to Trichoderma species. SIGNIFICANCE AND IMPACT OF THE STUDY: The discovery that ergokonin A could be an inhibitor of glucan synthesis, having a structure very different to other inhibitors, increases the likelihood that orally active agents with this fungal-specific mode of action may be developed.

Animals↗
PubMed2001

Evaluation of Chlamydia pneumoniae 43- and 53-kilodalton recombinant proteins for serodiagnosis by Western Blot.

Chlamydia pneumoniae is a common cause of respiratory infection. It has also been shown to be associated with coronary heart disease. Two proteins that have been reported to be recognized frequently during human infection are proteins having molecular masses of 43 and 53 kDa. In order to develop a useful alternative serological test to the microimmunofluorescence (micro-IF) assay, recombinant 43-kDa and 53-kDa chlamydia-specific proteins were evaluated in dot blot and/or for comparison to the standard micro-IF test. Primers for amplification were derived from genome sequence information for two C. pneumoniae genes (CPn0809 and CPn0980) encoding 53-kDa proteins and four C. pneumoniae genes (CPn0562, CPn0927, CPn0928, and Cpn0929) encoding 43-kDa proteins of unknown function, which were Chlamydia specific and not found in Chlamydia trachomatis. The 53-kDa protein product of CPn0809 or the N-terminal 18-kDa portion had better specificity than any of the 43-kDa recombinants but was much less sensitive than micro-IF. In contrast, the 53-kDa protein encoded by CPn0980 was recognized by 11 of 12 (92%) acute-phase sera, 35 of 46 (76%) chronic sera, 0 of 12 micro-IF-negative sera (C. pneumoniae and C. trachomatis negative), and 1 of 12 (8%) C. pneumoniae negative, C. trachomatis positive sera. Thus, it appears that the 53-kDa protein encoded by CPn0980 has potential use for serodiagnosis of C. pneumoniae infection.

Antigens, Bacterial↗
PubMed2001

[Corrosion and haemocompatibility of 316L stainless steel with electroplated Rh film].

In this study, surface modification by electroplating Rh on 316L stainless steel was carried out in order to improve the corrosion resistance and blood compatibility of implants. XPS was used to characterize the Rh film. The corrosion behavior of 316L stainless steel with electroplated Rh and non-treated was studied in Tyrode's biological solution. Additionally, the haemocompatibility of 316L stainless steel with electroplated Rh was evaluated by preliminary hemolysis test. The results showed that the corrosion resistance of 316L stainless steel with electroplated Rh was improved, and hemolysis decreased, which indicated that electroplating Rh can improve the blood compatibility of 316L stainless steel.

Animals↗
PubMed2001

[Correction of polypronuclear zygotes in 31 cases by micromanipulation].

OBJECTIVE: To study the development of polypronuclear zygotes corrected by micromanipulation. METHODS: Thirty one cases of polypronuclear zygotes were corrected during September to December of 1999 through micromanipulation to remove supernumerary pronucleus from polypronuclear zygotes at 37 degrees C and observing their development 24 and 48 hours later to compare with the normal pre-embryos. RESULTS: 17 in 31 (55%) cases of corrected polypronuclear zygotes developed to 2 to 4-cell pre-embryoes 24 hours later. There was significant difference while compare with the normal zygotes. However 48 hours later the cleavage rate of the two group of preembryos was the similar. CONCLUSION: The correction of polypronuclear zygotes by micromanipulation may in some way cause damage to the cleavage ability in part of the zegotes, but the remaining can develope normally.

Cell Division↗
PubMed2001

[A clinical analysis of 102 cases of chronic n-hexane intoxication].

OBJECTIVE: Chronic n-hexane exposure can result in n-hexane intoxication which is mainly characterized by a series of manifestations of peripheral nerve lesions. The disease was sometimes misdiagnosed as "unknown multiple peripheral neuropathy". 102 cases of n-hexane intoxication were investigated and reported in order to call attention to the disease. METHODS: All the 102 cases, male 30, female 72; age 17 - 29, mean (21 +/- 3) were n-hexane workers. During the hospitalization the following data were collected: medical history, neurological check up, electromyogram, electrocardiogram, serum biochemical analysis, ophthalmologic study and the metabolite of n-hexane- the urinary 2, 5-hexanedione level. The airborne n-hexane levels of the working environment were also measured. RESULTS: The average incubation period of the 102 cases was (8.3 +/- 2.6) months. The average course of the disease was (12.1 +/- 4.2) months. Airborne n-hexane concentration of the working places ranged from 188.0 to 7,848.6 mg/m(3). The most common prodromes were headache, anorexia, dizziness and weight loss. The main clinical manifestations of the disease were ascending abnormal sensation. Sensory loss and dyskinesia began from the distant parts of the limbs. The patient had reduction or disappearance of tendon reflexes, weakness and muscle atrophy in the limbs. Electromyography showed a neuropathic pattern, which was parallel to the clinical symptoms and signs. Delayed worsening of symptoms and signs after cessation of n-hexane exposure was observed in some cases. All the 102 cases recovered totally after treatment with Vitamin B, Chinese traditional medicine, physical therapy and training. CONCLUSION: The main lesion of the disease is multiple peripheral neuropathy. Diagnosis should be made according to the history of n-hexane exposure, the typical clinical manifestations of peripheral neuropathy as well as the neuropathic changes on electromyography. Therapeutic measures for peripheral neuropathy of other etiologies may be used and the prognosis is optimistic if correct diagnosis is made and further exposure stopped.

Adolescent↗
PubMed2001

[Epidemiological investigation on incidence of bronchial asthma in urban population of Shenyang].

OBJECTIVE: Try to find out asthma incidence in urban population of Shenyang. METHOD: From December 1998 to June 1999, 24 176 residents (11 955 male and 12 221 female persons) living in two residential districts from an industrial and a cultural region were selected as subjects of epidemic investigation by random sampling. The subjects were asked questions concerning the epidemic investigation. The lung functions were measured for subjects suspicious for asthma. RESULTS: 299 cases (102 male and 197 female) were diagnosed as asthma. The incidence of asthma was 1.24% (male 0.85% and female 1.61%). The female incidence of asthma was significantly higher than that in male (P < 0.01). Of the asthma patients, 80 cases (26.76%) were found with heredity background in their families; and 73 cases (24.41%) were found complicated with COPD. CONCLUSION: The investigation basically reflected the true condition of asthma incidence in urban population of Shenyang.

Adolescent↗
PubMed2001

[Syntheses of polymer coated silica packing materials and their retention behaviors for reversed-phase liquid chromatography].

The polymer coated silica packings C or D with methylmethacrylate(MMA) or MMA-ethylene dimethacrylate(EDMA) monomer were prepared. For the packing materials the polymer coated degree, effects of cross-linking agent and retention behavior were characterized by diffuse reflectance infrared Fourier transform spectroscopy, elemental analysis, size exclusion chromatography and reversed-phase liquid chromatography. The results showed that polymer coated degree on silica depended on the amount of monomer, and the volume of micropore of the meterials, which was controlled more by the cross-linked structure than by the linear structure. The hydrophobicity, retention ratio and number of theoretical plate (80% methanol and 60% acetonitrile) of the packing materials in comparison with those of C18 are discussed. The polymer coated silica packings C and D showed the same stereoselectivity for separation of aromatic compounds, such as triptycene.

Benzene↗
PubMed2001

[Preparation and evaluation of phosphatidylcholine coated on silica as the biomembrane stationary phase].

The method of reverse phase evaporation is used to coat phosphatidylcholine(PC) directly on the surface of silica, which is used as biomembrane chromatographic solid phase to study the interactions between drugs and biomembrane. It was observed that the solid phase coated phosphatidylcholine had a good stability at 20 degrees C-30 degrees C, and the stability would be improved by the presence of appropriate amount of cholesterol in phosphatidylcholine. The content of cholesterol in phosphatidylcholine, the nature of buffer, the concentration of salt in buffer and the pH of mobile phase could all affect chromatographic retention of drugs on the prepared biomembrane column. Six compounds, polyethylene glycol, mannitol, salicylic acid, warfarin, hydrocortisone, and cortisone have been tested. The biomembrane chromatographic stationary phase coated PC with silica as matrices can be simply prepared and it is possible to simulate the human's physiological environment by the biomembrane chromatographic system, so it is a useful method to study drug absorption and distribution in human body.

Chromatography, Liquid↗