Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 793 records · Page 44Linked to original sources

PubMed2000

Natural antibody-induced intracellular signalling and growth control in C3H 10T1/2 fibroblast variants.

Cell-surface binding by natural antibody (NAb) places it well for controlling cell function directly through signalling. Flow cytometry revealed an instability of syngeneic NAb binding to C3H 10T1/2 fibroblast variants at 37 degrees, which could be partially reduced by H7, an inhibitor of the pivotal signalling serine/threonine kinase, protein kinase C (PKC). Cells coated with purified NAb at 4 degrees followed by a rise in temperature to 37 degrees showed an increase in membrane expression of introduced rat PKC-beta 1 and endogenous PKC-alpha, in the PKC-beta 1-overexpressing PKC-4 and v-H-ras-producing I3T2.1, respectively. Tyrosine phosphorylation of membrane-associated 60 000 MW protein including the tyrosine kinase src was markedly reduced. In addition, both the precoated NAb and numerous membrane molecules ranging from 20,000 to 220,000 MW were released into the supernatant, including the receptor-like protein tyrosine phosphatase alpha (RPTP-alpha). Furthermore, purified NAb reduced the growth of I3T2.1 cells in culture assessed as a decrease in total cell numbers and an increase in the proportion of cells in the G0/G1 phase of the cell cycle. Together, these data argue that the interaction of NAb with cell surface structures initiated a series of intracellular signalling events leading to the release of membrane molecules and over time the suppression of cell proliferation. This process could provide a biological mechanism for direct NAb control of activated cells in both physiological and pathological conditions.

Animals↗

PubMed2000

The Arabidopsis Cdc2a-interacting protein ICK2 is structurally related to ICK1 and is a potent inhibitor of cyclin-dependent kinase activity in vitro.

Cyclin-dependent kinases (CDKs) are important regulators of the eukaryotic cell division cycle. To study protein-protein interactions involving plant CDKs, the Arabidopsis thaliana Cdc2aAt was used as bait in the yeast two-hybrid system. Here we report on the isolation of ICK2, and show that it interacts with Cdc2aAt, but not with a second CDK from Arabidopsis, Cdc2bAt. ICK2 contains a carboxy-terminal domain related to that of ICK1, a previously described CDK inhibitor from Arabidopsis, and to the CDK-binding domain of the mammalian inhibitor p27Kip1. Outside of this domain, ICK2 is distinct from ICK1, p27Kip1, and other proteins. At nanogram levels (8 nM), purified recombinant ICK2 inhibits p13Suc1-associated histone H1 kinase activity from Arabidopsis tissue extracts, demonstrating that it is a potent inhibitor of plant CDK activity in vitro. ICK2 mRNA was present in all tissues analysed by Northern hybridization, and its distribution was distinct from that of ICK1. These results demonstrate that plants possess a family of differentially regulated CDK inhibitors that contain a conserved carboxy terminal but with distinct amino terminal regions.

Amino Acid Sequence↗

PubMed2000

Expression of the plant cyclin-dependent kinase inhibitor ICK1 affects cell division, plant growth and morphology.

The plant CDK inhibitor ICK1 was identified previously from Arabidopis thaliana with its inhibitory activity characterized in vitro. ICK1 displayed several structural and functional features that are distinct from known animal CDK inhibitors. Despite the initial characterization, there is no information on the functions of any plant CDK inhibitor in plants. To gain insight into ICK1 functions in vivo and the role of cell division during plant growth and development, transgenic plants were generated expressing ICK1 driven by the cauliflower mosaic virus 35S promoter. In comparison to control plants, growth was significantly inhibited in transgenic 35S-ICK1 plants, with some plants weighing <10% of wild-type plants at the 3 week stage. Most organs of 35S-ICK1 plants were smaller. There were also modifications in plant morphology such as shape and serration of leaves and petals. The changes were so drastic that 35S-ICK1 plants with strong phenotype no longer resembled wild-type plants morphologically. Analyses showed that increased ICK1 expression resulted in reduced CDK activity and reduced the number of cells in these plants. Cells in 35S-ICK1 plants were larger than corresponding cells in control plants. These results demonstrate that ICK1 acts as a CDK inhibitor in the plant, and the inhibition of cell division by ICK1 expression has profound effects on plant growth and development. They also suggest that alterations of plant organ shape can be achieved by restriction of cell division.

Arabidopsis↗

PubMed2000

Identification of a novel nuclear factor-kappaB sequence involved in expression of urokinase-type plasminogen activator receptor.

We have previously defined the promoter of human urokinase-type plasminogen activator receptor (uPAR) gene in a 188-bp fragment between bases -141 and +47 relative to the translation start site. Here, we report that a novel nuclear factor-kappaB (NF-kappaB)-like sequence (5'-GGGAGGAGTC-3') at -45 is located in the uPAR promoter and one of the two DNase I-protected regions, region I between bases -51 and -30. This NF-kappaB-like motif differs at positions 7-9 from the decameric consensus sequences of NF-kappaB (5'-GGGRNNYYCC-3' where R indicates A or G, Y indicates C or T, and N indicates any nucleotide) and at positions 1 and 7-9 from the kappaB-like motifs (5'-HGGARNYYCC-3' where H indicates A, C, or T, R indicates A or G, Y indicates C or T, and N indicates any nucleotide). Nuclear extracts from HCT116 cells contain proteins that specifically bind to the NF-kappaB-like site at position -45. Mutation of the NF-kappaB-like motif decreased the binding of transcription factor NF-kappaB and reduced the uPAR promoter activity in comparison with the wild-type sequences. Co-transfection with a dominant negative I-kappaB kinase-2 expression vector reduced uPAR promoter activity by 65-75%. These results demonstrate that a previously uncharacterized NF-kappaB motif is required for uPAR promoter activity.

5' Untranslated Regions↗

PubMed2000

Binding of the GABA(A) receptor-associated protein (GABARAP) to microtubules and microfilaments suggests involvement of the cytoskeleton in GABARAPGABA(A) receptor interaction.

GABA(A) receptor-associated protein (GABARAP) was isolated on the basis of its interaction with the gamma2 subunit of GABA(A) receptors. It has sequence similarity to light chain 3 (LC3) of microtubule-associated proteins 1A and 1B. This suggests that GABARAP may link GABA(A) receptors to the cytoskeleton. GABARAP associates with tubulin in vitro. However, little is known about the mechanism for the interaction, and it is not clear whether the interaction occurs in vivo. Here, we report that GABARAP interacts directly with both tubulin and microtubules in a salt-sensitive manner, indicating the association is mediated by ionic interactions. GABARAP coimmunoprecipitates with tubulin and associates with both microtubules and microfilaments in intact cells. The cellular distribution is altered by treatment with taxol, nocodazole, and cytochalasin D. The tubulin binding domain was located at the N terminus of GABARAP by using synthetic peptides and deletion constructs and is marked by a specific arrangement of basic amino acids. The interaction between GABARAP and actin might be mediated by other proteins. These results demonstrate the GABARAP interacts with the cytoskeleton both in vitro and in cells and suggest a role of GABARAP in the interaction between GABA(A) receptors and the cytoskeleton. Such interactions are presumably needed for receptor trafficking, anchoring, and/or synaptic clustering. The structural arrangement of the basic amino acids present in the tubulin binding domain of GABARAP may aid in recognition of the potential of tubulin binding activity in other known proteins.

Actin Cytoskeleton↗

PubMed2000

Sequential treatment of SH-SY5Y cells with retinoic acid and brain-derived neurotrophic factor gives rise to fully differentiated, neurotrophic factor-dependent, human neuron-like cells.

A rapid and simple procedure is presented to obtain nearly pure populations of human neuron-like cells from the SH-SY5Y neuroblastoma cell line. Sequential exposure of SH-SY5Y cells to retinoic acid and brain-derived neurotrophic factor in serum-free medium yields homogeneous populations of cells with neuronal morphology, avoiding the presence of other neural crest derivatives that would normally arise from those cells. Cells are withdrawn from the cell cycle, as shown by 5-bromo-2'-deoxyuridine uptake and retinoblastoma hypophosphorylation. Cell survival is dependent on the continuous presence of brain-derived neurotrophic factor, and removal of this neurotrophin causes apoptotic cell death accompanied by an attempt to reenter the cell cycle. Differentiated cells express neuronal markers, including neurofilaments, neuron-specific enolase, and growth-associated protein-43 as well as neuronal polarity markers such as tau and microtubule-associated protein 2. Moreover, differentiated cultures do not contain glial cells, as could be evidenced after the negative staining for glial fibrillary acidic protein. In conclusion, the protocol presented herein yields homogeneous populations of human neuronal differentiated cells that present many of the characteristics of primary cultures of neurons. This model may be useful to perform large-scale biochemical and molecular studies due to its susceptibility to genetic manipulation and the availability of an unlimited amount of cells.

Apoptosis↗

PubMed2000

Vascular anatomic variations in second toe transfers.

To devise a new classification of vascular variations in second toe transfer we analyzed the anatomic details of the first dorsal metatarsal artery in 304 cases of second toe transplantation and the venous structure in 200 cases. According to location, the arterial vascularity was classified as superficial (18% of cases), intramuscular (54%), inframuscular (23%), and absent (5%). According to diameter, it was classified into large (16%), medium (64%), and small (20%). Based on branching pattern, the artery was classified into ramifying type (88%), main trunk (4%), and fine branch type (8%). The venous drainage of the second toe was categorized as greater saphenous vein main trunk type, greater saphenous vein fine branch type, dorsal digital vein main trunk type, and dorsal digital vein fine branch type. Variations of the first dorsal metatarsal artery are common. Classification should be done according to its location, diameter, and branching pattern at the toe web. Regardless of location, big vessels entering the second toe are the most important attribute for successful outcome.

Adolescent↗

PubMed2000

Decreased expression of thioredoxin and glutaredoxin in placentae from pregnancies with pre-eclampsia and intrauterine growth restriction.

Pre-eclampsia is one of the major contributors to perinatal morbidity. This study was performed to test a hypothesis which suggests that pre-eclampsia is associated with inadequate control by the thioredoxin system and other related reducing systems. Placental tissue from normal pregnancies (NC), severe pre-eclampsia with fetuses small for gestational age (SPE), mild pre-eclampsia with fetuses small for gestational age (MPE) and pregnancies with small fetuses for gestational age without any sign of pre-eclampsia (IUGR) was collected immediately after delivery. The mRNA levels for thioredoxin and glutaredoxin were determined using a solution hybridization method and the distribution of the proteins in a normal placenta was analysed by immunohistochemistry. Results showed that the thioredoxin mRNA level in the SPE group was decreased to one third of the level in the NC group. Also the IUGR group showed a significant decrease. The glutaredoxin mRNA level in the SPE group was one half of that seen in the NC group. There was significant correlation between the mRNA levels for thioredoxin and glutaredoxin, both in the normal and growth restricted pregnancies. We conclude that the thioredoxin and glutaredoxin reducing systems are affected in placenta from pregnancies with pre-eclampsia and/or growth restriction of fetuses, and that the decrease correlates to the severity of the condition.

Cell Nucleus↗

PubMed2000

Tumour volume estimated by computed tomography as a predictive factor in carcinoma of the tongue.

This retrospective study evaluated tumour volume, estimated by computed tomography (CT), as a predictive factor in carcinoma of the tongue. Tumour volume was measured from pretreatment CT scans of 20 consecutive patients, followed up for at least 3 years, and this measurement was compared with tumour volume estimated from pathological specimens. T-stage and CT-derived tumour volume were compared with the clinical and pathological status of the nodes, and with the outcome of treatment. The measurement of tumour volume derived from CT correlated well with measurements derived from pathological examination, and tumour volume also predicted overall treatment failure. The disease-specific survival rate was 100% for patients with low-volume tumours (<13 cc) compared with 79% for those with stage T1 and T2 tumours.CT is a reliable way of measuring the volume of tumours in carcinoma of the tongue, and tumour volume is useful adjunct to the clinical tumour-node-metastases staging system.

Adult↗

PubMed2000

Vascular osteomuscular autograft prefabrication using coral, type I collagen and recombinant human bone morphogenetic protein-2.

In 20 male Sprague-Dawley rats, 10 pieces of L-shaped coral combined with type I collagen and recombinant human bone morphogenetic protein-2 (rhBMP-2) and 10 discs (diameter 5 mm) were wrapped in the gracilis muscle, and left pedicled on the femoral vessels. Untreated coral was buried in muscle at a distant control site in 4 animals. After 3 weeks, autografts were examined for the shape of new bone, vascular patency, and induction of bone. In all grafts in viable tissue, heterotopic bone was formed. The shape of the new bone was the same as that of the coral, and there was no significant inflammatory reaction. Part of the coral in the composite was absorbed. Bone was not formed in any of the control sites. Coral and type 1 collagen are effective as a carrier for BMP to prefabricate vascular osteomuscular autografts with designed shape. There is a potential clinical application for BMP to bioengineer microvascular free flaps with intrinsic skeletal muscle for maxillofacial reconstruction.

Animals↗

PubMed2000

Cerebral arteriovenous malformations associated with aneurysms--a report of 10 cases and literature review.

We analysed 10 cases of arteriovenous malformations (AVMs) associated with aneurysms and reviewed the literature in order to confirm the clinical characteristics of AVMs associated with aneurysms. The mean incidence of aneurysms in our AVM population was 9.1% and the average age was 38 years. The ratio of male to female was 1.3 to 1. The aneurysms (40-96%) were often located on a feeding artery and seldom (23%) at an arterial bifurcation. The mortality rate was 0-26% in surgically managed patients and 38-60% in conservatively treated patients. The combination of intracranial vascular lesions is not rare. Most patients presented with symptoms referable to their AVMs. Treating both lesions in a single operation is the best option. The prognoses for most patients was good.

Adolescent↗

PubMed2000

Induction of autologous graft-versus-host disease with cyclosporin A after peripheral blood stem cell transplantation: analysis of factors affecting induction.

BACKGROUND: Induction of autologous graft-versus-host disease after peripheral blood stem cell transplantation has not been studied well. OBJECTIVE: The purpose of this study was to analyze the factors that affect the development of autologous graft-versus-host disease. METHODS: Nineteen patients with non-Hodgkin's lymphoma underwent peripheral blood stem cell transplantation followed by the administration of cyclosporin A for 28 days (group A) or 21 days (group B) and IFN-gamma. RESULTS: Autologous graft-versus-host disease failed to develop in the any of the group A patients, who did not receive total body irradiation for conditioning and underwent the transplantation with unmanipulated peripheral blood stem cells, although cytotoxic activity against autologous lymphocytes was detectable in peripheral blood mononuclear cells obtained from all of them after the transplantation. Autologous graft-versus-host disease developed in 2 of 4 patients in group A who received enriched CD34(+) cells and in 7 of 11 patients who underwent conditioning with total body irradiation. Maculopapular erythema that was compatible with graft-versus-host disease developed on days 19 to 27 after the transplantation in these patients and resolved after 3 to 9 days without treatment. CONCLUSIONS: Either the depletion of regulatory cells from the graft by enrichment of CD34(+) cells or the abolition of the autoregulation by including total body irradiation in the conditioning regimen may be effective in inducing autologous graft-versus-host disease after peripheral blood stem cell transplantation. Three weeks of cyclosporin A therapy appears to be sufficient to induce autologous graft-versus-host disease in recipients of peripheral blood stem cells.

Adult↗

PubMed2000

Ductal carcinoma in situ of the breast--a review of diagnosis, treatment and outcome in a hospital-based Norwegian series.

Between 1980 and 1994, 71 women with histologically proven ductal carcinoma in situ (DCIS) were diagnosed at Ullevål Hospital; bilateral tumours were found in two patients. Surgical treatment was mastectomy (42 lesions) or local excision (31 lesions). Median follow-up time was 7.2 years. Ten patients experienced a local recurrence, seven of which were invasive carcinomas. The actuarial 5-year local recurrence rate was 22% after local excision. A multivariate analysis found that tumour size was the only factor that predicted local recurrence after local excision. An analysis of relative survival in a nation-wide material of 832 DCIS patients in the period 1980 to 1994 demonstrates that relative survival after a DCIS diagnosis is almost 100%, irrespective of surgical treatment of the initial lesion.

Adult↗

PubMed2000

The trimmed-haplotype test for linkage disequilibrium.

Single-marker linkage-disequilibrium (LD) methods cannot fully describe disequilibrium in an entire chromosomal region surrounding a disease allele. With the advent of myriad tightly linked microsatellite markers, we have an opportunity to extend LD analysis from single markers to multiple-marker haplotypes. Haplotype analysis has increased statistical power to disclose the presence of a disease locus in situations where it correctly reflects the historical process involved. For maximum efficiency, evidence of LD ought to come not just from a single haplotype, which may well be rare, but in addition from many similar haplotypes that could have descended from the same ancestral founder but have been trimmed in succeeding generations. We present such an analysis, called the "trimmed-haplotype method." We focus on chromosomal regions that are small enough that disequilibrium in significant portions of them may have been preserved in some pedigrees and yet that contain enough markers to minimize coincidental occurrence of the haplotype in the absence of a disease allele: perhaps regions 1-2 cM in length. In general, we could have no idea what haplotype an ancestral founder carried generations ago, nor do we usually have a precise chromosomal location for the disease-susceptibility locus. Therefore, we must search through all possible haplotypes surrounding multiple locations. Since such repeated testing obliterates the sampling distribution of the test, we employ bootstrap methods to calculate significance levels. Trimmed-haplotype analysis is performed on family data in which genotypes have been assembled into haplotypes. It can be applied either to conventional parent-affected-offspring triads or to multiplex pedigrees. We present a method for summarizing the LD evidence, in any pedigree, that can be employed in trimmed-haplotype analysis as well as in other methods.

Alleles↗

PubMed2000

Participants in the Program of All-Inclusive Care for the Elderly (PACE) demonstration: developing disease-impairment-disability profiles.

The Program of All-Inclusive Care for the Elderly (PACE) builds on On Lok's community-based care and financing model for disabled elderly people who are state certified as eligible for nursing home care. Yet PACE's diverse population has not been fully described. We obtained data for a complete cross-section of PACE participants from early 1997 (N = 2,917). Using grade-of-membership analysis, we classified participants on the basis of their specific diseases, impairments, and disabilities. The classification was reviewed by a physician panel to produce clinical profiles, which were then validated against participants' PACE tenure, demographics, supports, and health. Cognitive impairment, incontinence, and activities of daily living disabilities were influential in producing eight types, which correspond predictably to responses in tenure (the more disabled, ill types likely to be in PACE longer), demographics, health, and informal support.

Activities of Daily Living↗

PubMed2000

Thioredoxin expression in human myometrium and fibroids.

Thioredoxin is a small multifunctional protein which acts as a dithiol hydrogen donor for ribonucleotide reductase in DNA synthesis. Thioredoxin participates in the regulation of different metabolic processes, such as changes in the activity of different enzymes, receptors or transcription factors. The aim of the present study was to determine possible differences in the expression of thioredoxin between myometrium and fibroids in women during different periods of life. Thioredoxin mRNA concentrations were determined in myometrial and fibroid tissues obtained from women during the menstrual cycle, during treatment with an analogue of gonadotrophin releasing hormone (GnRH agonist), in the postmenopausal period (PMP) and during pregnancy. The concentration of thioredoxin mRNA was measured by a solution hybridization method. The localization of thioredoxin protein was examined by immunohistochemistry. There were significantly lower levels of thioredoxin expression in both fibroids and myometrium from GnRH agonist treated and PMP women in comparison with the pregnant women. No difference in thioredoxin expression was found between myometrium and fibroids from the same woman or between myometria from uteri with or without fibroids in the same patient group. Thioredoxin expression in uterine fibroids does not seem to be up-regulated, but changes in response to the endocrine conditions in a similar way to that observed in the myometrium.

Adult↗

PubMed2000

The expression of glutaredoxin is increased in the human cervix in term pregnancy and immediately post-partum, particularly after prostaglandin-induced delivery.

Glutaredoxins are glutathione disulphide oxidoreductases catalysing disulphide reductions via a redox active disulphide. We have examined the presence of glutaredoxin in the human cervix, and its differential expression during cervical remodelling in term pregnancy and immediately post-partum as compared to the non-pregnant state. Cervical biopsies were obtained from 24 term-pregnant and 24 post-partal women, of which 10 were taken after spontaneous delivery, 10 after prostaglandin-induced delivery and four after mifepristone-induced delivery, all obtained within 15 min after delivery. Six non-pregnant women served as controls. The tissues were analysed for the glutaredoxin mRNA levels using a solution hybridization method. Glutaredoxin mRNA was expressed in the human cervix, the level increased > or =2-fold at term pregnancy and immediately post-partum. The level of cervical glutaredoxin mRNA from prostaglandin E(2)-treated women was 3-fold higher than after spontaneous ripening and delivery. Localization of glutaredoxin was visualized with immunohistochemistry in cervices from two post-partal women, and was compared to that of thioredoxin. We conclude that glutaredoxin may be involved in the regulation of cervical ripening in humans, particularly in the inflammatory reaction seen during this process. Glutaredoxin mRNA levels are up-regulated after prostaglandin treatment, which is effective and the most commonly used substance for cervical priming and induction of labour.

Abortifacient Agents, Steroidal↗

PubMed2000

Identification of epididymal stones in diverse rooster populations.

The epididymal region of the male reproductive tract is essential for sperm maturation, and dysfunction of this region results in infertility. Adult roosters have been observed to develop epididymal stones and consequently have reduced fertility. Efferent ductule cysts were first observed in White Leghorn roosters ages 18 to 26 wk. By 26 wk of age, the cysts had become solid, irregularly shaped, yellow-green stones primarily containing calcium (48%). The number and size of stones (9 to 160 microm, largest diameter) increased with age in affected males. Incidence ranged from 0 to 94% within rooster flocks surveyed. Stones have also been observed in broiler breeder roosters. Histological analysis of Leghorn and broiler breeder reproductive tracts revealed chronic inflammation with abundant interstitial mononuclear cell infiltrates. The normal, highly folded structure of efferent ductules was replaced by a thin, eroded epithelial layer with few luminal sperm. Abnormal areas were found interspersed with normal areas of epithelium. Broiler breeder male fertility trials demonstrated that birds with stones compared with normal males had reduced fertility following both natural mating (24.8+/-10.5% vs. 66.1+/-7.2%) and artificial insemination (47.8+/-16% vs. 82.0+/-6%). At 62 wk of age, testis weight (14.2+/-1.4 g vs. 20.5+/-1.2 g), daily sperm production (8.1+/-1.3 x 10(8) vs. 12.3+/-0.8 x 10(8) sperm per testis per day), and circulating testosterone concentrations (0.9+/-0.3 vs. 2.6+/-0.4 ng/mL) were all significantly reduced in males with stones. In conclusion, we are reporting a new dysfunction of the rooster reproductive tract that affects diverse bird populations and decreases fertility.

Animals↗