Search PubMed⌕ Search

Biomedical subjects

H Chen

Publications and source records attributed to H Chen.

At least 523 records · Page 29Linked to original sources
PubMed2000

[Identification of quantitative trait loci associated with fruit traits in watermelon [Citullus lanantus (Thanb) Mansf] and analysis of their genetic effects].

In this study, we mapped and characterized quantitative trait loci (QTL) affecting watermelon fruit traits. A total of 118 F2 progenies derived from the cross 97103 (which is a cultivar with higher total soluble solids concentration, thin rind, susceptible to Fusarium wilt disease) x PI296341(which is a wild germplasm with lower total soluble solids concentration, thick rind, resistant to Fusarium wilt disease) were used to construct a 96-markers map in watermelon. By using interval mapping 4 QTLs for total soluble solids concentration, 5 QTLs for hardness of rind, 2 QTLs for thickness of rind, 3 QTLs for weight of simple fruit, and 6 QTLs for weight of one thousand grain seeds were identified. In addition, the explained variations, additive effects and dominance effects for all detected QTLs were analyzed.

Chromosome Mapping↗
PubMed2000

[Matching of brain sections based on fourier descriptors].

We developed an algorithm based on Fourier Descriptors(FD) to match brain sections and specially aimed to pool electro-physiological data from individual animals and composite the results on a single brain. To test this algorithm, curvilinear features were first extracted from each section image of the midbrain of the rat resulting in three closed boundaries. A set of boundaries of 38 consecutive sections was then taken as standard templates for matching with any other brain sections processed in a similar way. Each section was represented by Fourier descriptors of these boundaries. Matching was done by minimizing the similarity function between an experimental brain section and the set of standard templates. This algorithm has been successfully used for the study of functional organization of AM-sound sensitive auditory neurons in the midbrain.

Algorithms↗
PubMed2000

[Selected CD34+ cells transplantation: a primary clinical report].

OBJECTIVE: CD34+ is an immunophenotype of hematopoietic stem cells/progenitors. CD34+ cells selection in vitro may deplete T-cells 4-5 logs and tumor cells 3-4 logs. It will benefit to mismatched related donor allo-transplantation and autologous transplantation of tumor diseases. METHODS: 19 patients aged 29 (5-52) years were treated by allo- (n = 5) or auto-PB CD34+ cells transplantation (n = 14). Grafts from fifteen patients with various disorders (3 lymphomas, 6 multiple myelomas, 2 SLE, 1 Sjogren's syndrome, 2 breast cancer and 1 medulloblastoma) and five haploidentical donors for leukemia patients (1 ALL-CR2, 2 AML-rel, 1 CML-CP and 1 MDS-RAEB) were isolated using magnetic-activated cell sorting (CliniMACS, Milteny Biotech, Germany). RESULTS: After separation, purity of CD34+ cells was > 97%. Depletion of CD34 negative cells was extensive: CD3+ 2.6-4.6 logs, CD4+ > 5 logs, CD8+ 4.6-> 5 logs, and CD19+ 1.2-3.1 logs. 19 patients who received selected CD34+ cells transplantation (CD34+ CT) were followed up for 11(1-20) months. Overall survival(OS) was 13/19 (68.4%) cases. 1/5 patients with haploidentical transplant had disease free survival for 19 months. 12/14(85.7%) auto-CD34+ CT achieved overall survival(OS). CONCLUSION: Selected CD34+ cells transplantation significantly decreases the incidence of > II GVHD and depletes tumor cell contamination. This approach may be useful to haploidentical or unrelated donor transplantation. It also benefits autologous transplant in various tumor disorders.

Adolescent↗
PubMed2000

[Neutrophil activation in pathogenesis of preeclampsia].

OBJECTIVE: To investigate the effect of neutrophil activation on pathogenesis of preeclampsia. METHODS: In 22 pregnant women with preeclampsia and 21 normal pregnant women at third trimester, neutrophil activation was examined by flow cytometry to assess the CD11b expression, and the levels of plasma endothelin-1 (ET-1) and serum NO2- were also measured with no-equilibrium radio-immunoassay and with Griess assay respectively. RESULTS: The expression of neutrophil CD11b was significantly elevated in women with preeclampsia compared with that of normal pregnant women at third trimester [the mean fluorescence index of CD11b were 439.1 +/- 169.1 and 321.2 +/- 166.3 respectively, P < 0.05], the plasma ET-1 level and serum NO2- concentration in preeclampsic women [(61.4 +/- 48.2) ng/L and (20.4 +/- 5.2) mumol/L, respectively] were both significantly increased compared with those in the normal pregnancy women [(29.3 +/- 20.9) ng/L and (15.5 +/- 4.8) mumol/L, respectively], (P < 0.01). The mean fluorescence index of CD11b was significantly correlated with plasma ET-1 level and serum NO2- concentration (r = 0.312 and 0.382, respectively, P < 0.05). But the correlation between the plasma ET-1 level and serum NO2- concentration was not found (r = 0.227, P > 0.05). CONCLUSIONS: The neutrophil CD11b expression is significantly elevated in preeclampsia. The increased neutrophil activation may cause the damage of vascular endothelium and result in compensatory increase of NO release in endothelial cells. It suggests that the neutrophil activation may play a key role in pathogenesis of preeclampsia.

Adult↗
PubMed2000

[Clinicopathological studies on bone marrow involvement of non-Hodgkin's lymphoma].

OBJECTIVE: To investigate the relationship between pathomorphological features and clinical manifestations of non-Hodgkin's lymphoma (NHL) with bone marrow involvement (BMI). METHODS: Plastic-embedded section of bone marrow biopsy was stained with H-Giemsa-E. Immunotyping of NHL was performed immunohistochemically. RESULTS: A total of 70 patients with NHLBMI(male: 52, female: 18; median age: 49 years) was studied. There were 20 patients with T cell-lymphoma and 50 patients with B cell-lymphoma. The extent of bone marrow involvement was minimal in 15 cases, moderate in 16 cases and severe in 39 cases. Bone marrow involvement was of interstitial type in 23 cases, nodular type in 7 cases, and mixed type in 18 cases and diffuse type in 22 cases. The frequency of splenomegaly in nodular type NHLBMI was significantly higher than that in any other type. Nodular type NHLBMI occurred mainly in B cell-lymphoma. Lymphoma cell leukemia (LCL) developed in 14 of 39 (35.9%) cases of NHL with severe bone marrow involvement which was significantly more frequent than that in NHL with mild and moderate bone marrow involvement. CONCLUSION: Difference in the extent and pattern of bone marrow involvement in NHL is related to clinical manifestations. Bone marrow biopsy helps evaluate response to treatment.

Adolescent↗
PubMed2000

[One-dimensional impact dynamic response of cancellous bone].

In this paper a one-dimensional dynamic response of cancellous bone to impact loading is investigated. It is demonstrated, based on the studies with scanning electron microscope, cancellous bone could be viewed as a cellular solid consisting of an interconnected skeleton filled with medulla. A two-phase poroelastic model is introduced to describe the cancellous bone, in which the tissue(material) densities of the skeleton and medulla are assumed to be unchangeable while the corresponding apparent densities are changeable due to the change of volume fraction, the governing equations are derived for the case of a linear poroelastic solid skeleton saturated with an inviscid medulla. Under the impact loading, responses of the skeleton displacement and stress as well as the medullary pressure are obtained with the use of Laplace transform technique. The computational result shows that the cancellous bone is provided with certain features similar to those appearing in viscoelastic solids, which means that the responses do not only depend on time, but furthermore depend on previous loading history. It is worth paying attention to the result that the medullary pressure can be negative. This point is due to the recovery of the skeleton after unloading whereas the medulla is not squeezed out but absorbed into the pores by suction.

Biomechanical Phenomena↗
PubMed2000

[Automated analysis technology of electrocardiograms].

Study of detection and analysis methods for electrocardiograms(ECGs) has been developed for more a decade. But it is still existing some problems because of patient idiosyncrasy. The automated analysis of ECGs was simply summarized at the present for existing problems and with possible way to solve those troubles. We have reviewed preprocessing methods of waveform detection of ECGs and diagnosis techniques of arrhythmia.

Arrhythmias, Cardiac↗
PubMed2000

[Studies on relationship between exposure to low concentration of mixed benzene and lower quality of semen and very early fetal loss].

OBJECTIVE: To study the effects of exposure to low concentration of mixed benzene on their semen quality and very early fetal loss (VEFL) in the occupational population. METHODS: Environmental monitoring and biological monitoring were conducted in 126 employees exposed to mixed benzene and 60 unexposed ones selected from a large petrochemical corporation and a large chemical fiber corporation. Quality of semen in 70 male workers in the exposed group and 90 male internal controls and 132 male external controls were analyzed, and urinary beta-human chorionic gonadotropin (beta-hCG) was determined for 42 female exposed workers and 49 female internal controls and 118 external controls. RESULTS: 1. Exposure to mixed benzene mainly existed in low concentrations (0.7-27.0 mg/m3) in the petrochemical corporation, and urine concentration of t, t-MA in the workers correlated significantly to benzene concentration in ambient air of the workshops (r = 0.64, P = 0.03). 2. The sperm progression and motility in the exposed (1.97 +/- 0.63 and 0.55 +/- 0.16) and the internal control (1.97 +/- 0.69 and 0.55 +/- 0.17) groups were significantly (P < 0.05) lower than those in the external control group (2.56 +/- 0.61 and 0.60 +/- 0.13), however, the sperm abnormality rates in the exposed and internal control groups were significantly (P < 0.01) higher than those in the external control group, and the summary abnormality rate of sperm in the exposed group (85.71%) was higher than that in the internal (70.00%) and external control (76.51%) groups (P < 0.05). 3. The incidence rates of the VEFL in female workers and the cyclic occurrence of VEFL both in the exposed and internal control groups (10.42% and 9.60%) were higher than those in the external control group (5.09%), with statistical significance (P < 0.05). CONCLUSIONS: Exposure to low concentration of mixed benzene maybe correlated with the declined quality of semen and VEFL in occupational workers, and urinary t, t-MA and beta-hCG can be used as biomarkers of exposure and effect, respectively.

Abortion, Spontaneous↗
PubMed2000

HIV prevention community planning and communities of color: do resources track the epidemic?

The Centers for Disease Control and Prevention (CDC) funds provided to state, local, and territorial health departments for HIV-prevention activities are prioritized with the substantial involvement of HIV-prevention community planning groups (CPGs). This article examines whether or not these funds (more than $261 million in fiscal year 1998) are allocated in a way that mirrors the HIV/AIDS epidemic in terms of race/ethnicity. AIDS prevalence data were used to reflect disease burden, and were compared to budget data submitted by health departments to the CDC. The budget data report expenditures by race/ethnicity for two major types of activities: (1) health education and risk reduction (more than $104 million); and (2) counseling, testing, referral, and partner notification (more than $91 million). The rank order correlation between funding and AIDS prevalence data for the five specific racial/ethnic categories was .900 (n = 5, p < .05) for health education and risk reduction (HERR) activities, and 1.000 (n = 5, p < .05) for counseling, testing, referral, and partner notification (CTRPN) activities. From 1997 to 1998, the proportion of funds targeted and accounted for by race/ethnicity increased from 79 percent to 88 percent for HERR, and from 71 percent to 84 percent for CTRPN activities. With regard to race/ethnicity, health departments and CPGs appear to be actively targeting and accounting for HIV prevention resources, and we will argue that relatively small changes in counseling and testing resources for African-American and Latino/Latina communities would result in a close match between AIDS prevalence data and devoted resources.

Centers for Disease Control and Prevention, U.S.↗
PubMed2000

[Population growth, distribution pattern and sampling technique of Thrips palmi on eggplant].

Population growth of Thrips palmi Karny on eggplant (Solanum melongena L.) were analyzed by mathematical models. The rate of population increase (r) of the adults and immature (instars 1-2) T. palmi were estimated to be 0.0630 and 0.0801 respectively in the open fields, and 0.0983 and 0.1036 respectively in the greenhouse. K value of logistic curve of T. palmi was estimated to be 33.90 in the greenhouse, and 23.50 in the open fields. The relationship between mean crowding (M*) and mean density (M) of T. palmi per eggplant leaf were estimated by Iwao's M*-M regression. The regression equation of adult and immature T. palmi on eggplant were: M* = 0.6011 + 1.468M and M* = 7.2515 + 2.064M respectively. The regression equation of the number of adult and immature was M* = 7.5138 + 1.9119M. When the population density of the adults and immature T. palmi per eggplant leaf were 10 to 100, the number of sampling should be 78 to 44.

Animals↗
PubMed2000

[Quantitative characteristics of rare and endangered Castanopsis kawakamii population].

In this paper, a new self-adaptive model for population growth, i.e. S = exp(alpha ln2(1 + ce-rt) + beta ln(1 + ce-rt) + gamma) was established, which combined Logistic, Smith, Gompertz, Gui-Lawson, Zhang-Logistic and Liu-Logistic models. Estimations with genetic algorithm showed that the new model was more suitable than other models to simulate the actual growth trend of Castanopsis kawakamii population.

China↗
PubMed2000

[Soil moisture dynamics in forest land and wasteland of Loess Plateau].

The dynamics of soil moisture stored in a wasteland and in a forest land in the sub-humid climate region of the Loess Plateau was measured with neutron moisture meter for three successive years. Within the depth of 0-320 cm, the increment of soil water in the test 3 years was respectively -165.7 mm, -15.2 mm and -115.2 mm at the upper and lower position on north slopes and the lower position on south slope of the wasteland. Soil water increased by 17.2 mm at the upper position on north slope of the Chinese pine forest land, after > 380 mm water was consumed yearly by tree transpiration. It is suggested that forest land is essentially different from wasteland in soil water income/expense. The necessity of conducting the approaches for gaining available water of forest land was put forward.

Seasons↗
PubMed2000

Safety and immunogenicity of lyophilized, live attenuated hepatitis A vaccine in non-human primate model.

OBJECTIVE: To evaluate the safety and immunogenicity of lyophilized, live attenuated hepatitis A vaccine (H2 strain) in rhesus monkeys. METHODS: Nine adult rhesus monkeys were used as experimental animals. The rhesus monkeys without anti-HAV were divided randomly into the aqueous vaccination group (4 rhesus monkeys), the lyophilized vaccination group (3 rhesus monkeys), and the control group (2 rhesus monkeys). Monkeys were inoculated by intramuscular injection, with control monkeys being inoculated with Minimum Essential Medium Eagle (MEM). Following vaccination, the monkeys were observed for the development of diarrhoea and other adverse side-effects, such as changes in appetite, frequency of defaecation and stool consistency for seven days. At the weeks 2, 3, 4, 6, 8, 10 and 12 positnoculation, the peripheral blood was collected from all animals and assayed for anti-HAV and alanine aminotransferase (ALT) and aspartate aminotransferase (AST), at weeks 0, 4 and 8 postinocuation, needle-biopsy specimens were taken at weeks 0, 4, 8 and 12, all monkeys were sacrificed and tissue samples were taken from liver, lung, heart, kidney and brain for pathological examination at week 12. RESULTS: Animals were immunized with a dose of 7.0 logTCID50/ml which is stable after freeze-drying. During the 12-week observation, no animals showed abnormal elevations of liver enzymes (ALT and AST) and no change in appetite or activity. Two monkeys (one in the aqueous group and the other in lyophilized group) showed possible lesions at week 8. The lyophilized vaccine, in addition to eliciting an anti-HAV IgG response similar to aqueous vaccine (P > 0.05), also showed IgM anti-HAV response at week 2 which was not observed with aqueous vaccine. CONCLUSIONS: These results demonstrate that lyophilized, live hepatitis A vaccine is safe and highly immunogenic in primates, supporting its further evaluation in human clinical studies.

Animals↗
PubMed2000

[A clinical prospective study on maternal-fetal transfusion transmitted virus infection].

OBJECTIVE: To observe the transfusion transmitted virus (TTV) infection rate in gravidas and parturients, and explore the route of maternal-fetal transmission. METHODS: TTV infection was detected by nest-polymerase chain reaction (n-PCR) in the serum of 60 healthy gravidas and parturientes. Once parturient infection was identified, the latices and the umbilical blood were examined for TTV infection as well. Meanwhile, a group of non-pregnant healthy women was tested as control. RESULTS: The infection rate of observation group was 28.33%, while in the control group it was 7.57%. The difference of the two groups was significant (P < 0.001). Of the TTV positive parturientes, TTV infection rate of their latices was 27.27%, but none of the umbilical blood samples showed TTV positive. CONCLUSIONS: The TTV infection rate of gravidas and parturientes is higher than that of non-pregnant healthy women. TTV can infect newborns through latices, however, there is no vertical maternal-fetal transmission.

DNA Virus Infections↗
PubMed2000

Expression of the MAGE-1 gene in human hepatocellular carcinomas.

OBJECTIVE: To further investigate the expression of MAGE-1 gene in hepatocellular carcinoma (HCC). METHODS: The tumors and adjacent liver tissue from 45 HCC patients and liver tissue from 28 non-HCC patients (16 with liver cirrhosis and 12 with normal liver) were characterized by RT-PCR. A 421 bp PCR product from a cDNA fragment spanning exons 1, 2 and 3 was sequenced. The HLA type was assayed by standard ELISA in 43 HCC patients. RESULTS: Thirty-two of 45 tumor tissues from HCC patients expressed MAGE-1 mRNA (71.1%). In contrast, MAGE-1 mRNA was not detected in adjacent tissues. Three were found to have point mutations at 3 identical sites resulting in the substitution of two amino acid residues. The most frequent HLA types in 43 HCC patients were: HLA-A2, 53.5%; A11, 25.6%; A24, 20.9%; A33, 20.9%; HLA-B13, 28.3% and B35, 23.2%. Expression of HLA-A33 (20.9%) was higher in HCC patients than that predicted in the normal Chinese population (8.8%). There was no discemable correlation between MAGE-1 expression and alpha-FP level, tumor size and hepatitis B or C virus infection. The identification of peptides which are restricted by haploptypes other than A1 should increase the opportunity for peptide based immunotherapy. CONCLUSIONS: This study shows that MAGE-1 mRNA is highly expressed in HCC tumor tissue in Chinese patients. Previously unreported point mutations in the MAGE-1 gene are described and may also provide additional opportunities for immunotherapy.

Amino Acid Sequence↗
PubMed2000

[The efficacy and safety of domestic luteinizing hormone-releasing hormone analogue and low-dose norethindrone "add-back" therapy in the treatment of endometriosis].

OBJECTIVE: To study the efficacy and safety of combining domestic luteinizing hormone-releasing hormone analogue(LHRH-a) with low-dose norethindrone in the treatment of endometriosis. METHODS: Seventy-seven women with endometriosis were randomized into one of the following two groups. Group A (n = 36) were treated with LHRH-a (150 micrograms/d, i.m.) plus norethindrone (2.5 mg/d, p.o.) and group B (n = 41) received only LHRH-a (150 micrograms/d, i.m.) for 3 to 6 months. Symptoms and signs were recorded before and after the treatment. Liver and renal functions, lipid and bone metabolism and speed of sound (SOS) in the tibia were also examined at the same time. All data were analyzed using paired and grouped Student's t-tests. RESULTS: Total subjective symptom scores of group A showed 82% decrease at 3 months and 94% at 6 months of treatment (P < 0.01). Reductions in endometriotic foci were 34% and 61% at 3 and 6 months, respectively (P < 0.01). Of group B, there were 77% and 90% decreases in total subjective symptom scores at 3 and 6 months of treatment (P < 0.01). Reductions of 37% and 38% in endometriotic foci were observed at 3 and 6 months, respectively (P < 0.01). Liver and renal functions and fast blood sugar of both groups were all in normal range. Triglyceride (TG), apolipoproteinA (ApoA), serum calcium, phosphorus and alkaline phosphatase levels of group B increased significantly after treatment. And significant differences between the two groups were observed. There's no change of SOS in the tibia within or between the two groups before and after treatment. The percentages of hemorrhage in the group A and B were 18% and 38%, respectively. The percentages of hot flush and the other vasomotor symptoms were 14% and 41%, respectively (P < 0.01). CONCLUSIONS: Domestic LHRH-a combined with low-dose norethindrone was effective in the treatment of endometriosis. It could also improve the symptom of hypoestrogenemia, decrease hemorrhage rete and bone turn-over.

Adult↗