Biomedical subjects

H Wen

Publications and source records attributed to H Wen.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Inhibition of cultured human retinal pigment epithelial cell by tissue-type plasminogen activator].

PURPOSE: To study the inhibition effects of human retinal pigment epithelial (RPE) cells by tissue-type plasminogen activator(tPA). METHODS: The effects of tPA on human RPE cells proliferation were studied by viable cell counting and methyl thiazolyl tetrazolium (MTT) colorimetric assay. Flow cytometry (FCM) analysis was used to examine RPE cell cycles. RESULTS: The proliferation of human RPE cells could be inhibited by 0.1-3 micrograms/ml tPA (P < 0.05). The effects of inhibition were depended on the drug density and the action time directly (P < 0.01). 5 micrograms/ml tPA was deadly-toxic to human RPE cells. FCM revealed that the cells in S phase increased 9.8% (P < 0.05) and cells in G2M phase decreased 6.6% (P < 0.05), compared to controls. CONCLUSION: tPA at a certain dose range and period could inhibit human RPE cells proliferation without deadly-toxicity. The human RPE cells growth could be interfered in S phase by tPA.

Cell Division↗

PubMed2000

RBP95, a novel leucine zipper protein, binds to the retinoblastoma protein.

We recently identified a novel cDNA encoding a retinoblastoma protein (pRb)-associated protein. It was named RBP95, which was composed of 838 amino acid residues with a calculated molecular size of 94,789 Da. Northern blot analysis showed a single mRNA of about 4. 5 kb ubiquitously expressed in human tissues. RH mapping results showed that RBP95 is mapped to chromosome region 16p11.2-11.1. Sequence analysis indicated that RBP95 contains a conserved pRb-binding motif LXCXE. Interaction between pRb and RBP95 was confirmed in vivo and in vitro. This interaction requires the LXCXE motif of RBP95 and the entire pocket region of pRb. Each point-mutant of the conserved amino acid residues in pRb-binding motif of RBP95 would destroy its interaction with pRb. RBP95 also contains a basic region leucine zipper and could homodimerize through its leucine zipper region. RBP95 was located in the nucleus with a special pattern when expressed as a GFP fusion in HeLa cells. All these findings suggested that RBP95, a new member of pRb-associated protein, may function as a regulation factor in the process of RNA polymerase II-mediated transcription and/or transcriptional processing.

Amino Acid Sequence↗

PubMed2000

Epidemiology of alveolar echinococcosis in Xinjiang Uygur autonomous region, China: a preliminary analysis.

The Xinjiang Uygur autonomous region (XUAR) in north-western China is known to be endemic for Echinococcosis multilocularis, the causative agent of human alveolar echinococcosis (HAE). Despite regular reports of HAE cases in their region, very little is known about the local epidemiology of the disease or the transmission of E. multilocularis. The epidemiology of HAE in Xinjiang has now been investigated by the analysis of data collected from the medical records of 157 clinical cases who had attended the four main hospitals in the region. These data indicate that the disease is relatively common in the Altai, western Junggar, and Tianshan mountain ranges, whereas the Tarim and Junggar basins are likely to be of low endemicity. The prevalence of the disease in the Kunlun mountains is not clear. Semi-nomadic groups, especially those of Kazakh or Mongol origin, have a higher risk of infection than other ethnic groups. Prevalence of the disease in humans appears to be correlated with aspects of the local climate, such as annual precipitation and temperature. Red foxes, Microtinae, Ochotona spp. and Marmota spp. may be important hosts of E. multilocularis in the XUAR, sustaining the transmission cycles of the parasite.

Adolescent↗

PubMed2000

Feasibility of biomedical applications of Hall effect imaging.

Hall effect imaging is a new technique for mapping the electrical properties of a sample. Its principle has been demonstrated in two- and three-dimensional phantom images. Based on the experimental data and theoretical understanding of this technique developed over the past few years, this paper addresses the most relevant question for biomedical applications: whether Hall effect imaging is ultimately applicable to complex biological systems such as the human body. The arguments are given at the basic physics level, so that the conclusion is independent of current technology status. These arguments are corroborated with imaging data of an aorta sample. The conclusion is that Hall effect imaging is not suited for quantifying the electrical constants in complex biological samples. This technique is able to produce high-resolution volume images of samples in vitro that reflect their electrical heterogeneity. However, quantitative measurements of electrical constants are not practical for complex samples.

Algorithms↗

PubMed2000

Antifungal therapy for treatment of cryptococcal meningitis.

OBJECTIVE: To compare the curative effects of three different antifungal regimens in the treatment of cryptococcal meningitis. METHODS: Twenty-two patients were divided into 3 groups: Group I was given intravenous amphotericin B alone or combination with flucytosine therapy. Group II received intravenous fluconazole alone or combination with flucytosine. The treatment of Group III was divided into two steps, where the patients received intrathecal amphotericin B plus intravenous amphotericin B with or without intravenous fluconazole until the mycological culture of cerebrospinal fluid (CSF) turned negative, followed by oral fluconazole or itraconazole as maintenance therapy until direct microscopic examination of CSF showed negative once a week for three consecutive weeks. RESULTS: Of the twenty-two patients, 17 (77.3%) were cured, 2 (9.1%) improved, 3 (13.6%) died, and one (4.5%) relapsed. Of the 8 patients in Group I, 5 were cured, 2 improved, one died and one relapsed; Of the 4 patients in Group II, 2 were cured, and 2 died; All the 10 patients in Group III were cured without any recurrence. CONCLUSION: The two-step therapeutic regimen may be suited to the treatment of cryptococcal meningitis.

Adolescent↗

PubMed2000

[Clinical study on treatment of nasopharyngeal carcinoma by radio- and chemotherapy with supplementary moxibustion on Shenque point].

OBJECTIVE: To evaluate the effect of supplementary moxibustion in treating III, IV a stage nasopharyngeal carcinoma (NPC) with radio- and chemotherapy. METHODS: Fifty-six cases of NPC were randomly divided into two groups, 28 in each group. They were treated with radiotherapy in routine or chemotherapy adopting AD protocol. Salt-separated moxibustion on Shenque (Ren 8) point was given to the treated group from beginning of radio- and chemotherapy for 30 times as one therapeutic course. RESULTS: The remission rate in the two groups after radio- and chemotherapy was not different significantly. The toxic and side-effect occurrence was less in the treated group than that in the control group (P < 0.05). The 5-year local control rates of NPC and cervical lymphnode were 85.7% and 85.0% in the treated group, which were higher than those in the control group (78.6% and 78.9%). The 5-year survival rate in the two groups were 50.0% and 35.7% respectively. After radio- and chemotherapy, the blood content of malonyldialdehyde (MDA), middle molecular substance and sulfhydryl reduced the SOD activity ascended in the treated group, the difference was significant as compared with those in the control group (P < 0.05, P < 0.01). CONCLUSION: The supplementary moxibustion on Shenque point could obviously reduce the toxic side-effect of advanced NPC patients treated with radio- and chemotherapy.

Acupuncture Points↗

PubMed2000

[Experimental observation on anaphylaxis induced by Echinococcus infection in Meriones unguiculatus].

OBJECTIVE: To observe the anaphylaxis induced by Echinococcus granulosus or E. multilocularis (E. g. and E. m.) infection in Meriones unguiculatus. METHODS: 56 and 48 gerbils were intraperitoneally inoculated with E. g. protoscoleces and E. m. tissue homogenate. After three months, the anaphylactic responses initiated by intraperitoneal challenge injection with E. g. cystic fluids or partially purified antigen or E. m. metacestode homogenate antigen were observed. IgE antibody and direct eosinophilic leukocyte count (DELC) were detected at pre-postchallenge. RESULTS: The infection rates for E. g and E. m. in 56 and 48 gerbils were 89.3% and 97.9%, respectively. Among these groups, the lowest rate of anaphylaxis was 62.5%, the highest was 100%. The lowest rate of anaphylactic shock was 12.5%, and the highest 16.7%. After the gerbis were infected with E. g. and E. m., both IgE antibody and DELC increased gradually. At 60 min post challenge, IgE antibody level were significantly decreased, while DELC showed a sharp increase. CONCLUSION: Anaphylaxis could be induced in gerbils by Echinococcus infection followed by a challenge injection. Different antigens lead to different and degrees among the anaphylactic responses in the gerbils, however, there were no significant differences between E. g. and E. m. infections in gerbils.

Anaphylaxis↗

PubMed1999

Identification of a novel gene encoding a p53-associated protein.

p53 exerts important physiological functions in cell-cycle control, gene regulation, cell differentiation, apoptosis and tumor suppression by interacting with many cellular proteins. Using the yeast two-hybrid system, we screened a HeLa cDNA library and identified a novel gene encoding a p53-binding protein (p53BP3). The full-length cDNA of p53BP3 was isolated from a HeLalambdagt10 cDNA library. This predicted protein was composed of 815 amino acids. Sequence analysis indicated that p53BP3 contained two bipartite nuclear localization signals and was confirmed to be a nuclear protein. FISH mapping results showed that this novel gene was located at human chromosome 12, region p11.2-p12.1. Northern blot analysis suggested that p53BP3 was broadly expressed in human tissues. A further study showed that p53BP3 had a homologue in mouse.

Amino Acid Sequence↗

PubMed1999

Clinical implication of expression of platelet-derived endothelial cell growth factor (PD-ECGF) in metastatic lesions of uterine cervical cancers.

The platelet-derived endothelial cell growth factor (PD-ECGF) level was significantly (P < 0.05) increased in 8 of 40 metastatic lymph node lesions of uterine cervical cancers. The prognosis of the eight patients with high PD-ECGF (>10,000 pg/mg protein) in metastatic lymph node lesions was extremely poor. On the other hand, the 24-month survival rate of the 32 patients with low PD-ECGF (<10,000 pg/mg protein) in metastatic lymph node lesions was 75%. This indicates that PD-ECGF may contribute to the advancement of metastatic lesions, and that the PD-ECGF level in metastatic lesions may be a prognostic indicator.

Adult↗

PubMed1999

Simultaneous binding of two protein kinases to a calcium-dependent potassium channel.

Large-conductance calcium-dependent potassium channels are subject to modulation by protein kinases, phosphatases, and other signaling proteins, and it has been inferred from electrophysiological experiments that signaling proteins sometimes can be intimately associated with these channels in a regulatory complex. We show here that endogenous protein kinase activity coimmunoprecipitates with both native and recombinant Drosophila Slowpoke (dSlo) calcium-dependent potassium channels. Coimmunoprecipitation experiments using antibodies against several protein kinases demonstrate that dSlo can bind simultaneously to the Src tyrosine kinase and to the catalytic subunit of the cAMP-dependent protein kinase (PKAc). Both kinases can phosphorylate the channel in Drosophila heads and in heterologous host cells. The PKAc binds directly to a 172-amino acid region in the C-terminal domain of dSlo, without the intervention of regulatory subunits or anchoring proteins, and channel phosphorylation by PKAc is not required for this binding interaction. In contrast, several phosphorylatable tyrosine residues in dSlo are important for Src binding. The results are consistent with the idea that an ion channel can act as a scaffold for its own specific set of modulatory enzymes.

Animals↗

PubMed1999

Improved field of view-reducing gradient insert: artifacts and application to cardiac imaging.

An improved homogeneity-spoiling local gradient insert has been constructed and built into the patient bed to reduce its impact on bore size and setup time. It allows the field of view to be reduced without introducing aliasing artifacts. Image quality and artifacts were evaluated for pulse sequences relevant to cardiac imaging. The utility of the insert is demonstrated by a contrast-enhanced perfusion study, in which the reduced field of view allowed a 25% increase in resolution and one more slice to be imaged per heartbeat. J. Magn. Reson. Imaging 1999;10:209-215.

Adult↗

PubMed1999

DENSE: displacement encoding with stimulated echoes in cardiac functional MRI.

Displacement encoding with stimulated echoes (DENSE) was developed for high-resolution myocardial displacement mapping. Pixel phase is modulated by myocardial displacement and data spatial resolution is limited only by pixel size. 2D displacement vector maps were generated for the systolic action in canines with 0.94 x 1.9 mm nominal in-plane resolution and 2.3 mm/pi displacement encoding. A radial strain of 0.208 was measured across the free left ventricular wall over 105 ms during systole. DENSE displacement maps require small first-order gradient moments for encoding. DENSE magnitude images exhibit black-blood contrast which allows for better myocardial definition and reduced motion-related artifacts.

Animals↗

PubMed1999

High-resolution strain analysis of the human heart with fast-DENSE.

Single breath-hold displacement data from the human heart were acquired with fast-DENSE (fast displacement encoding with stimulated echoes) during systolic contraction at 2.5 x 2.5 mm in-plane resolution. Encoding strengths of 0.86-1.60 mm/pi were utilized in order to extend the dynamic range of the phase measurements and minimize effects of physiologic and instrument noise. The noise level in strain measurements for both contraction and dilation corresponded to a strain value of 2.8%. In the human heart, strain analysis has sufficient resolution to reveal transmural variation across the left ventricular wall. Data processing required minimal user intervention and provided a rapid quantitative feedback. The intrinsic temporal integration of fast-DENSE achieves high accuracy at the expense of temporal resolution.

Heart↗

PubMed1999

Comparison of 3D BOLD functional MRI with spiral acquisition at 1.5 and 4.0 T.

In order to investigate the merit of high field strength for BOLD-contrast-based functional magnetic resonance imaging (fMRI) studies, multishot gradient-echo fMRI experiments during motor cortex activation were performed on 1.5- and 4.0-T scanners with equivalent hardware, on the same volunteers. In these studies, artifactual vascular enhancement related to inflow effects was minimized, and large brain areas were covered by using a 3D scan technique. Temporal signal stability was optimized by using spiral readout gradients. The sensitivity for detection of activated regions was assessed by measuring the number of "activated voxels" and their average t score in predefined regions of interest. When comparing fMRI experiments with the same total scan time, performed on six subjects, and with acquisition parameters optimized for each field strength separately, the 4.0-T scanner proved to give superior results, with a 70% greater number of activated voxels and a 20% higher average t score for the activated voxels.

Humans↗

PubMed1999

A comparison among four regimens of itraconazole treatment in onychomycosis.

The purpose of this study was to compare the efficacy of different dosage regimens in the management of onychomycosis with itraconazole and to determine the results of a further 1-week intermittent pulse treatment in non-cured patients. In this study, 153 patients were randomly allocated to four groups. Patients in group A were treated with daily doses of 100 mg for 3 months in the case of fingernail onychomycosis and for 4 months in the case of toenail onychomycosis. Patients in the other groups received a intermittent pulse therapy, in which the drug was taken for 1 week, then discontinued for 3 weeks, three cycles for fingernail and four cycles for toenail infection. The daily doses were 400 mg (group B), 300 mg (group C) and 200 mg (group D). After therapy, non-cured patients were treated further with one cycle in which the daily dose was 400 mg. Patients were subsequently observed for 9 months and efficacy was assessed by mycological examination and the growth of unaffected nails. At the end of the therapy, the cure rates in the four groups were 19.1% (A), 15.2% (B), 18.9% (C) and 17.9% (D), and no significant differences were found between each of B, C, D and A. At the end of the study, the cure rates were 76.2%, 91.3%, 78.4%, 28.6% respectively. The group that received further treatment had a cure rate of 55.6% at the end of the first month and of 83.3% in the second month. Drug tolerability was equally good in the four groups. Intermittent pulse therapy with a daily dose of 400 mg had the highest cure rate. Treatment of improved but non-cured patients with a dose of 400 mg intermittent pulse therapy markedly increased the cure rate. All treatment regimens were well tolerated.

Adolescent↗

PubMed1999

Ontogeny of water transport in rat brain: postnatal expression of the aquaporin-4 water channel.

Brain water transport is poorly understood at the molecular level, and marked changes occur during brain development. As the aquaporin-4 (AQP4) water channel protein is abundant in brain, the expression levels and subcellular distribution of this protein were examined during postnatal development. This study focused on the cerebellum, which showed the same pattern of AQP4 development as the rest of the brain. Semiquantitative immunoblotting revealed very low levels of AQP4 in the first postnatal week. A pronounced increase was noted in the second week, from 2% of adult level at postnatal day 7 (PN7) to 25% at PN14. At PN1 and PN3 immunofluorescence microscopy revealed weak labelling, mainly in radial processes (Bergmann fibres) and at the pial surface. Between PN7 and PN14 the labelling underneath the pia showed a strong increase, and immunoreactivity also appeared around blood vessels throughout the cerebellum. High-resolution immunogold electron microscopy revealed that the subpial and perivascular labelling was restricted to glial end feet, notably to those plasma membrane domains that were apposed to the basal laminae. At no stage was there any evidence of neuronal AQP4 labelling, and AQP1, -2, -3 and -5 proteins were not detected in the neuropil. Riboprobes to AQP4 mRNA produced a particularly strong in situ hybridization signal in glial cells between PN7 and PN14, corresponding to the stage of the most rapid increase of AQP4 protein. The time course and pattern of AQP4 expression suggests that this aquaporin plays an important role in brain water and K+ homeostasis from the second week of development.

Age Factors↗

PubMed1999

Angiogenesis in endometriosis and angiogenic factors.

Among angiogenic factors, VEGF secreted from activated macrophages under the influence of ovarian steroids, IL-8 expressed in endometrial stromal cells, and basic FGF expressed in endometriotic tissue and PD-ECGF expressed in lining epithelial cells independently of the sex steroidal milieu might contribute to the characteristic advancement of angiogenic lesions in endometriosis in individual manners. Copyrightz1999S.KargerAG,Basel

Adult↗

PubMed1999

Progestin regulation in tumor growth of female genital tract cancers.

The irregular response to progestins directly in tumor growth might be caused by dominant negative progesterone receptor (PR) mutants and the damage to PR-A expression. Progestin treatment as an anti-angiogenic therapy would be less effective in the PR-mutated tumors. Therefore, various anti-angiogenic inhibitors must be used in progestin-refractory and progestin-dependent tumors.

Endothelial Growth Factors↗