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Biomedical subjects

F H Kong

Publications and source records attributed to F H Kong.

14 recordsLinked to original sources
PubMed2001

Social approval and facilitation in predicting modeling effects in alcohol consumption.

PURPOSE: An important question for alcohol abuse prevention and treatment is whether individuals with high needs for social approval, or those who drink heavily in social contexts, are particularly vulnerable to modeling effects in alcohol consumption. METHODS: Male and female heavy social drinkers (N=202), as distinguished by these cognitive and situational variables, participated in a multisession dyadic modeling effects study along with a same-sex confederate model who exhibited alternating patterns of heavy and light consumption in an experimental barroom. RESULTS: Subjects with high needs for social approval, and those who tend to drink heavily in social contexts, were particularly vulnerable to imitating directional changes in modeled drinking levels across heavy and light consumption experimental sessions. Additionally, modeling effects were revealed, including reductions in drinking levels, regardless of individual characteristics such as demographics or levels of intoxication achieved on "usual drinking occasions." IMPLICATIONS: Findings suggest that individuals exhibiting high needs for social approval, and those who tend to drink heavily in social contexts, may benefit from (1) befriending lower risk models and (2) prevention and/or intervention efforts to reduce risk for substance use by reducing excessive needs for social approval and/or reducing exposure to social contexts where heavy drinking and related risk behavior is normative.

Adult↗
PubMed2000

Optimal sampling times in bioequivalence tests.

In bioequivalence studies, drug formulations are compared in terms of bioavailability parameters such as the area under the concentration-time curve (AUC), the maximum concentration (Cmax), and the time to maximum concentration (t(max)). Accuracy in measuring these parameters directly affects the accuracy of bioequivalence tests. Because the number of blood draws per patient is limited, the blood collection times must be spaced so that concentration-time curve measurements can produce accurate bioavailability parameter estimates. This paper describes an optimization approach for calculating optimal time designs for one-compartment models, but is sufficiently general for other compartmental models. Simulation indicates that the optimal design improves the accuracy of AUC estimation.

Area Under Curve↗
PubMed2000

[Repair of nasal columella defect with long slender tubed flap].

OBJECTIVE: To introduce the clinical application of long slender tubed flap constructed with "bridge" technique in the repair of nasal columella defect. METHODS: From March 1968 to August 1998, 18 cases with complicated nasal columella defects were repaired with long slender tubed flaps. Among the 18 tubed flaps, 13 cases were designed on the medial side of the upper arm and 5 cases on the longer cervical region paralleling the clavicle. The tubed flaps were 2.0 to 2.5 cm wide and 11 to 15 cm long. The length of the "bridge" was 3 to 7 cm. RESULTS: No flap necrosis or other complications occurred. Postoperative follow-up was 3 to 60 months. The reconstructed columellae showed satisfactory contour, good texture and color, and satisfactory resistance to injury. CONCLUSION: By using the "bridge" technique, tubed flap can be made long and slender enough to provide relatively abundant tissue with adequate circulation and delicate contour. Combined with strict case selection, long slender tubed flaps can bring excellent functional and cosmetic outcomes in the repair of nasal columella defects including those with partial defect of the nasal tip, ala, septum, or defect of adjacent soft tissue. However, this method is relatively time-consuming.

Adolescent↗
PubMed1998

A stochastic approximation algorithm with Markov chain Monte-carlo method for incomplete data estimation problems.

We propose a general procedure for solving incomplete data estimation problems. The procedure can be used to find the maximum likelihood estimate or to solve estimating equations in difficult cases such as estimation with the censored or truncated regression model, the nonlinear structural measurement error model, and the random effects model. The procedure is based on the general principle of stochastic approximation and the Markov chain Monte-Carlo method. Applying the theory on adaptive algorithms, we derive conditions under which the proposed procedure converges. Simulation studies also indicate that the proposed procedure consistently converges to the maximum likelihood estimate for the structural measurement error logistic regression model.

Journal Article↗
PubMed1998

[The diversity of human hematopoietic stem/progenitor cells: IX. Cell-cycles kinetics related macromolecules DNA, RNA and protein contents in CD34+ hematopoietic cells of human bone marrow].

DNA, RNA and PRO comprise the bulk of macromolecules in cells, which have been proven to play an important role in regulating cell cycle transverse capacity, cell division, growth, and size. Simultaneous analysis of these moieties could provide more comprehensive and accurate information on cell cycle kinetics. In this study, DNA, RNA and PRO contents related to cell cycle kinetics in CD34+ hematopoietic cells of human bone marrow were measured to understanding the cell cycle kinetic features in CD34+ hematopoietic cells. For this reason, CIMS-100 immunomagnetic isolator, a novel isolation system, was used to enrich efficiently CD34+ hematopoietic cells from human bone marrow. The purity of enriched CD34+ hematopoietic cells determined by both FACS and APAAP staining is ranging from 90%-95%. Cellular DNA, RNA and PRO were stained with fluorochromes propidium iodide, pyronin Y and fluorescein isothiocyante respectively The fluorescence intensities reflecting the DNA, RNA and PRO content of individual cell were analyzed in FACS can by different excitation wavelengthes. DNA, RNA and PRO contents in CD34+ hematopoietic cells were far lower than these of bone marrow mononuclear cells, only being 34 +/- 3% (DNA), 48 +/- 21% (RNA) and 62 +/- 14% (PRO) of BMMNCs respectively. Collectively, these data combined with previous results from both ours and others indicated that CD34+ hematopoietic cells are indeed an unique cell population, not only in reconstitute of hematopoietic and immunological functions, but also in cell cycle kinetics. This is, to our knowledge, the first detailed report on the analysis of DNA, RNA and PRO contents related to cell cycle kinetics in CD34+ hematopoietic cells. And the results provide more direct evidence that the majority of CD34+ hematopoietic cells are in resting state.

Antigens, CD34↗
PubMed1997

[The diversity of human hematopoietic stem/progenitor cells: VIII. Sterological features of CD 34+ hematopoietic cells isolated from human bone marrow].

Human CD 34+ hematopoietic cells, a distinctive cell population containing hematopoietic stem/progenitor cells, have the capability to highly self-renewal, differentiation into all lineages of committed progenitor cells and reconstitution of both long-term hematopoiesis and immune functions after transplantation. In our previous study, the morphological, ultrastructural and cytochemical features concerning CD 34+ hematopoietic cells obtained by a two-step isolated systems of CIMS-100/FACS 440 with 100% purity were depicted. Based on these observations on CD 34+ hematopoietic cells under light microscope, SEM and TEM, we recently analyze the sterological features of CD 34+ hematopoietic cells with the aid of Quantimet 970 automatic image analyser so that the three-dimension structures regarding CD 34+ hematopoietic cells could be further made clear. By a series of measures including image scan-->modulus transform-->shadow correction-->image store-->statistical analysis, some morphometric parameters of CD 34+ hematopoietic cells were obtained as the followings: diametrs 3.490-6.741 microns, perimeters 11.776-26.240 microns, surface area 9.565-35.686 microns2, form factors 1.048-1.840, nucleus-plasma ratio 0.55-0.72, mean light density 0.17675-0.65100, integral light density 2717.217-46661.000. These morphometric data combined with our previous results from morphology, ultrastructure and functional subsets of CD 34+ hematopoietic cells strongly demonstrate that CD 34+ hematopoietic cells are really a heterogenous population. The possible reasons causing heterogeneous are close associated with either different functional subsets or differentiation lineages. To our knowledge, this is the first identification of sterological features of CD 34+ hematopoietic cells.

Antigens, CD34↗
PubMed1996

[The diversity of human hematopoietic stem/progenitor cells. I. Two-color flow cytometric analysis of the different functional subpopulations of CD 34+ hematopoietic stem/progenitor cells riched from human bone marrow].

In hematopoiesis; the human CD 34 protein is a strict developmental stage-specific antigen that marks hematopoietic stem/progenitor cells, suggesting that it plays an essential role in hematopoiesis. More recently, it has been demonstrated that hematopoietic cells expressing the CD 34 antigen constitute various heterogeneous cell populations in which each CD 34+ subset was associated with commitment to a particular lineage, and differed from other's in reconstituting hematopoiesis. In this report, we have assessed the different functional subpopulation of CD 34+ hematopoietic stem/progenitor enriched from human bone marrow using Isolex TM 50 system according to the strategy on immunomagnetic separation of positive selection. CD 34+ cell population of high purity (> 90% CD 34+) was analyzed by means of double staining procedure of flurorescein conjugated monoclonal antibodies on the two-color FACAcan or FACS 440. Eight cell subsets of at least of bone marrow CD 34 hematopoietic stem/progenitor cells have been defined by undertaking a comparative coexpressing of CD 71, CD45, CD 33 and HLA-DR antigens on CD 34 hematopoietic stem/progenitor cells. The frequencies of various subsets in two illustrative are as following: 1). CD 34+/CD 71- and CD 34+/CD 71+ (23.43%-56.6% versus 33.4%-66.6%): 2). CD 34+/CD45- and CD 34+/CD45+ (80.8%-82.5% versus 8.1%-11.2%): 3). CD 34+/CD 33- and CD 34+/CD 33+ (20.4%-80.6% versus 14.6%-64.8%): 4). CD 34+/DR- and CD 34+/DR+ (6.3%-11.0% verus 82.8%-85.5%). Immunological double color staining of IGSS-APAAP was also used to further analyse the CD 34+ cell subsets as above-mentioned, the results were very similar to those obtained by FACScan. Our data indicate that CD 34+ hematopoietic cell fraction is far from being a uniform cell population, and many works regarding biological properties and regulation mechanism of different subsets of CD 34+ hematopoietic stem/progenitor cells are being carried out.

Antigens, CD↗
PubMed1991

The pharmacophore of debromoaplysiatoxin responsible for protein kinase C activation.

Protein kinase C is physiologically activated by 1,2-diacyl-sn-glycerol in the S configuration. The enzyme is also powerfully activated by structurally diverse tumor promotors. A model has been developed that demonstrates how the various tumor promotors and diacylglycerols can all be accommodated by the same binding site of the kinase. One prediction of this model concerns the structural nature of the pharmacophore in the tumor promotor debromoaplysiatoxin. This prediction is realized by synthesizing the analogs with the deduced pharmacophore and demonstrating that they are potent activators of protein kinase C. These findings provide strong experimental support for our structural model of protein kinase C activation.

Animals↗
PubMed1990

Human leukocyte antigens -A, -B, -C, and -DR and nasopharyngeal carcinoma in northern China.

We observed HLA associations in patients with nasopharyngeal carcinoma from northern China. There was an increased risk of nasopharyngeal carcinoma associated with HLA-B35 and a difference in the HLA association between patients with early- and late-onset disease. The frequency of B35 was significantly higher in patients than in control subjects, especially in early-onset patients (less than 30 years old). Late-onset patients had a higher frequency of DR2 as compared with normal subjects.

Adult↗