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Biomedical subjects

F Kong

Publications and source records attributed to F Kong.

At least 55 records · Page 3Linked to original sources
PubMed1999

Comparative analysis and serovar-specific identification of multiple-banded antigen genes of Ureaplasma urealyticum biovar 1.

Ureaplasma urealyticum is a causative agent of nongonococcal urethritis and is implicated in the pathogenesis of several other diseases. The species is divided into 14 serovars and two biovars, of which biovar 1 is most commonly isolated from clinical specimens. Reported associations between individual serovars and diseases have been difficult to confirm because of practical difficulties with serotyping. The multiple-banded antigen (MBA) is the predominant U. urealyticum antigen recognized during infections in humans and probably has a significant role in virulence. The 5' end of the MBA gene is relatively conserved but contains biovar, and possibly serovar, specificity. The 5' ends of the MBA genes of standard strains of U. urealyticum biovar 1, consisting of serovars 1, 3, 6, and 14, were amplified, cloned into pUC19, and sequenced to identify serovar-specific differences. The 5' end of the MBA gene sequence of serovar 3 was identical with the previously published sequence and differed by only three bases from that of serovar 14. Significant differences between the MBA gene sequences allowed biovar 1 to be divided into two subgroups, containing serovars 3/14 and serovars 1 and 6, respectively, using primers UMS-125-UMA269 and UMS-125-UMA269'. Serovars 1 and 6 were distinguished by restriction enzyme analysis of the amplicon and/or by PCR specific for serovar 6. These methods were used to identify and type U. urealyticum in 185 (46.3%) of 400 genital specimens from women. Biovar 1 was detected in 89.2% and biovar 2 in 18.3% of positive specimens. Of 165 specimens containing U. urealyticum biovar 1, 22.2% contained more than one serovar and 46.7, 46.1, and 25.5% contained serovars 1, 3/14, and 6, respectively. U. urealyticum was found in a significantly higher proportion of pregnant women than in sex workers and other women attending a sexually transmissible diseases clinic (P < 0.01). The methods described are relatively rapid, practicable, and specific for serotyping isolates and for direct detection and identification of individual serovars in clinical specimens containing U. urealyticum biovar 1.

Antigens, Bacterial↗
PubMed1999

[Femtosecond time-resolved fluorescence spectra of LDS751].

The femtosecond time-resolved fluorescence depletion method has been introduced. In this method two beams of femtosecond laser was used. One excited the sample molecular to emit fluorescence. Then after specified time delay the second laser beam was introduced to deplete the fluorescence through the stimulate emission process. This method has been applied to LDS751 molecules in solution and its time-resolved fluorescence spectrum has been obtained.

Fluorescent Dyes↗
PubMed1999

[The calculation of Einstein spontaneous emission coefficients of HBr molecule].

The Einstein spontaneous emission coefficients of some rovibrational transitions of HBr molecule have been calculated from the first principle. The calculation is carried out for the deltav = 1 transitions of v < or = 7, J < or = 14 of R and P branches. A time-resolved Fourier transform infrared emission spectrum of the HBr molecule was recorded. The observed intensities of the spectral lines well agree the calculated coefficients.

English Abstract↗
PubMed1998

Induction of immunomodulating cytokines by a new polysaccharide-peptide complex from culture mycelia of Lentinus edodes.

The immunomodulating effect of a new polysaccharide-peptide complex from culture mycelia of Lentinus edodes (LE) was studied for elucidation of the mechanism of augmentation of cell-mediated immunity. RNA samples were isolated from the untreated and treated murine splenocytes and human peripheral blood mononuclear cells. RT-PCR was used to analyze the cytokine gene expression and bioassay was used to analyze the cytokine production. By administration of LE, the expression levels of IL-2 and TNF-alpha genes were augmented in the treated murine spleen mononuclear cells and human peripheral blood mononuclear cells. The production of IL-2 were augmented in the treated murine spleen mononuclear cells, and the production of TNF-alpha were augmented in the treated murine peritoneal exudate macrophages. The production of IL-2 and TNF-alpha were augmented in the treated human peripheral blood mononuclear cells. These results suggest that LE may induce Th immune responses.

Animals↗
PubMed1998

Thymic function can be accurately monitored by the level of recent T cell emigrants in the circulation.

Expression of the avian chT1 thymocyte antigen persists on a subpopulation of peripheral T cells enriched in the DNA deletion circles created by alphabeta and gammadelta TCR gene rearrangements. The chT1+ cells are evenly distributed among all of the peripheral T lymphocyte compartments. The levels of chT1+ T cells in the periphery gradually decline in parallel with age-related thymic involution, and these cells disappear following early thymectomy. Experiments in which variable numbers of the 14 thymic lobes are removed in young chicks indicate a direct correlation between the levels of circulating chT1+ cells and residual thymic mass. Measurement of recent thymic emigrants in the periphery thus provides an accurate indication of thymic function.

Aging↗
PubMed1998

[The constant-in time DC component in the time-resolved FTIR spectroscopy].

The direct current component in the interferogram of conventional FTIR spectroscopy is expressed by integral(infinity)0 B(sigma)dsigma. However, in time-resolved FTIR spectroscopy, the direct current component Idc(tau) also depends upon tau, the time which IR signal appears. Idc(tau) is then represented by integral(infinity)0 B(sigma, tau)dsigma, called as constant-in-time DC component by us. Idc(tau) is proportional to the signal intensity B(sigma). Idc(tau) can not be filtered by any band pass filter. After Fourier transforming, the Idc(tau) converts to a strong peak at 0cm(-1) in the IR spectrum. We call it as constant-in-time zero frequency signal Btau(0). Either Idc or Btau(0) can be used to monitor a variety of experimental conditions, such as the variation of gas pressure, laser intensity, the carbon deposition on the optics, etc. They can also be applied to measure the instrumental response time and the band pass frequency.

English Abstract↗
PubMed1997

Purification and light-dependent phosphorylation of a candidate fusion protein, the photoreceptor cell peripherin/rds.

The proteins peripherin/rds and rom-1 form a protein complex in the rims of photoreceptor outer segment disk membranes. Peripherin/rds plays an essential role in the morphogenesis and maintenance of disk membrane structure, with peripherin/rds gene mutations resulting in photoreceptor cell degeneration. We report two different chromatographic procedures for the purification of native peripherin/rds from bovine photoreceptor cell outer segments and show that the protein is a phosphoprotein that promotes membrane fusion in vitro. During one procedure, peripherin/rds was copurified in association with rom-1 by hyroxylapatite and Mono Q FPLC. During the other, it was purified free from rom-1 by concanavalin-A affinity chromatography and chromatofocusing. Analysis of homogeneous peripherin/rds from the second procedure showed that exposure of photoreceptor outer segments to light resulted in the incorporation of nearly 2 mol of phosphate per mole of peripherin/rds and a concomitant shift in the isoelectric point of the protein. In addition, we found that recombination of purified peripherin/rds into lipid vesicles increased membrane fusion, with more rapid fusion detected with phosphorylated peripherin/rds. In conclusion, studies with purified peripherin/rds reveal that the protein undergoes light-dependent phosphorylation and that it may function in membrane fusion.

Amino Acid Sequence↗
PubMed1997

Cytotoxic T lymphocyte responses to E6 and E7 proteins of human papillomavirus type 16: relationship to cervical intraepithelial neoplasia.

Cytotoxic T lymphocyte (CTL) responses to the human papillomavirus (HPV) type 16 E6 and E7 proteins were measured in 20 women with known HPV and cervical disease status. CTL assays were performed after stimulation with E6 or E7 fusion proteins using autologous B lymphoblastoid cells infected with vaccinia viruses expressing E6 or E7. CTL responses to E6 and E7 were detected in 6 (75%) of 8 and 5 (56%) of 9 HPV-16-positive women without cervical intraepithelial neoplasia (CIN), respectively. Responses to E6 or E7 were each detected in only 2 (29%) of 7 HPV-16-positive women with CIN. Responses to both antigens were found in 63% of women without CIN and 14% of those with CIN. CTL responses to E6 or E7 are more commonly detectable in HPV-16-positive women without CIN than in HPV-16-positive women with CIN, suggesting that CTL response may play a role in disease protection.

Adult↗
PubMed1997

Detection of HIV in oral mucosal cells.

OBJECTIVE: To determine the prevalence of HIV DNA and RNA and the morphologic localization of HIV in the oral cavity of HIV-seropositive subjects. DESIGN: A cross-sectional analysis of saliva, buccal scrapings and buccal biopsies from HIV-seropositive injecting drug users (IDUs). SUBJECTS AND METHODS: Whole saliva, buccal mucosal scrapings and buccal biopsies were obtained from HIV-seropositive and seronegative IDUs. Presence of HIV DNA and RNA was assessed by polymerase chain reaction (PCR) and reverse transcriptase PCR (RT-PCR). RT in situ PCR was used to detect HIV tat/rev RNA in buccal mucosal scrapings. Host-cell integrated HIV-proviral DNA in buccal biopsies was detected by in situ PCR. Presence of intact HIV viral particles in buccal scrapings was assessed by electron microscopy. RESULTS: HIV DNA was detected in 40% (18/45) and HIV RNA in 69.2% (25/36) of saliva samples from HIV-seropositive IDUs. Viral particles consistent with HIV were localized in inter-epithelial spaces by electron microscopy. RT in situ PCR revealed the presence of HIV tat/rev RNA in 36% (8/22) of the seropositive samples tested. CONCLUSIONS: Our results suggest that epithelial cells can be productively infected by HIV. Epithelial cells in buccal mucosa may acquire HIV in the basal layers through contact with submucosal HIV-positive lymphocytes and/or Langerhans' cells. HIV infection may also spread by inter-epithelial cell contact. As HIV infected cells mature they travel to more superficial layers and are shed into the oral cavity.

CD4-Positive T-Lymphocytes↗
PubMed1997

[Morphological and cytochemitry features of CD34+ hematopoietic cells isolated from human bone marrow].

OBJECTIVE: To explore the cytomorphological and cytochemitry features of CD34+ hematopoietic cells. METHODS: Highly purified CD34+ hematopoietic cells isolated from human bone marrow by a two-step method of immunomagnetic beads-FACS sorting were comprehensively examined. RESULTS AND CONCLUSION: CD34+ hematopoietic cells could be sorted into three types in light of morphology and cytochemical staining. Type I was considered as candidates for stem cells,which were most blastlike in morphology and slightly larger than lymphocytes in size with negative reactions to all cytochemical stainings. Type II was considered as multipotent progenitor cells, with sizes similar to small lymphocytes and negative reactions to all cytochemical stainings. Type III was identified as committed progenitor cells whose sizes were heterogeneous and whose reactions to cytochemical stainings ranged from +/- to + +.

Antigens, CD34↗
PubMed1997

[Detecting Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma genitalium in the urogenital tract].

OBJECTIVE: To epidemiological study of ureaplasma urealyticum (UU), mycoplasma hominis (MH) and Mycoplasma genitalium (MG) in the urogenital tract of different groups of people. METHOD: Polymerase chain reaction was used. Clinical urogenital tract specimens were collected from Beijing, Wuhan and Shantou STD patients and different groups of women in Beijing. RESULTS: The positive rates of UU and MH were higher than those of MG. In STD high risk group of people, the positive rates of mycoplasmas were correlated with the degree of sexual abuse positively. The positive rates of UU and MH in none STD high risk group of people could be relatively high, especially UU in the pregnant women. CONCLUSIONS: The relationship between infection and inhabitant of mycoplasmas in the urogenital tract is worthy to be studied further.

Adult↗
PubMed1996

Distribution of guanylate cyclase within photoreceptor outer segments.

Guanylate cyclases play an essential role in the recovery of vertebrate photoreceptor cells after light activation. Here, we have investigated how one such guanylate cyclase, RetGC-1, is distributed within light- and dark-adapted rod photoreceptor cells. Guanylate cyclase activity partitioned with the photoreceptor outer segment (OS) cytoskeleton in a light-sensitive manner. RetGC-1 was found to bind actin filaments in actin blot overlays, suggesting a mechanism for its association with the OS cytoskeleton. In retinal sections, this enzyme was immunodetected only in the OSs, where it appeared to be distributed throughout the disk membranes.

Amino Acid Sequence↗
PubMed1996

[Grouping and typing of Ureaplasma urealyticum].

OBJECTIVE: To construct the molecular biological methods to group and type Ureaplasma urealyticum. METHOD: Polymerase chain reaction was used to detect and group the 14 standard serotypes of Ureaplasma urealyticum. 272 urogenital tract clinical samples were detected and grouped. Random amplified polymorphic deoxyribose nucleic acid was used to study and compare Ureaplasma urealyticum serotypes 1, 3, 6, 14, 8, 10, 11. RESULTS: Detected by the polymerase chain reaction, group 1 had 403 bp amplified fragments, and group 2 had 448 bp amplified fragments. 272 urogenital tract clinical samples were detected. 72 cases were positive for ureaplasma urealyticum, 69 were positive for group 1, and 3 were positive for group 2. Random amplified polymorphic deoxyribose nucleic acid was used and gene fingerprinting maps of ureaplasma urealyticum serotypes 1, 3, 6, 14, 8, 10, 11 were constructed. CONCLUSIONS: Ureaplasma urealyticum grouping method was constructed by polymerase chain reaction. Among the urogenital tract clinical samples positive for Ureaplasma urealyticum, group 1 was more common to be positive. Random amplified polymorphic deoxyribose nucleic acid can be used as typing method of Ureaplasma urealyticum.

Base Sequence↗