Intracellular localization and trafficking of steroid receptors.
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CREB-Binding Protein↗
Biomedical subjects
C S Lim
Publications and source records attributed to C S Lim.
Expression of a non-inactivating K+ channel driven by a rat heat shock promoter increased the resting potential in Aplysia silent neurons.
We assessed the role of a non-inactivating K+ channel (aKv5.1) in the resting potential by overexpressing this channel by heat shock in the neurons. A reporter gene lacZ linked to a promoter region spanning from the -285 to the +88 base of the rat HSP70ib gene was induced 62.5-fold when this DNA construct was microinjected into the neurons of the marine mollusk Aplysia and treated with heat shock at 30 degrees C for 3 h. Using this efficient induction system, we induced the expression of aKv5.1 by heat shock in cultured, electrically silent neurons of Aplysia and examined its effect on the resting potential. The channel expression increased the resting potential by approximately 10 mV. This increase was specific to heat shock induction and abolished by treatment with TEA, a specific K+ channel blocker. These results provide the direct evidence that a low voltage-activated, non-inactivating K+ channel can contribute to the resting potential.
Animals↗
Neoadjuvant therapy in the treatment of high risk rectal carcinoma.
The management of rectal cancer remains a challenging and controversial area of surgical oncology. The spectre of local recurrence, with its' poor prognostic and palliative outcomes, is known to be highly dependent on operative technique and to vary widely between surgeons. The roles of radiotherapy and chemotherapy have been the subject of trials for 30 years and yet no consensus on treatment exists. In this review article we will summarise the evolution of radiotherapy and chemoradiation in the treatment of rectal cancer and evaluate the evidence available for the use of "neoadjuvant" chemoradiation. In particular, the role of adjuvant therapies in the setting of total mesorectal excision will be discussed.
Chemotherapy, Adjuvant↗
Response to chloroquine of Plasmodium vivax among South Korean soldiers.
The response to standard chloroquine treatment was evaluated, by microscopical examination of blood-smears, among 81 soldiers diagnosed with Plasmodium vivax malaria in South Korea in 1996. The smears were prepared pre-treatment and 3, 14 and 28 days after starting chemotherapy. Parasitaemias were determined after staining the smears with Giemsa's stain. Blood samples from the patients who were not smear-negative by day 3 were carefully checked for parasites, by staining smears with Acridine Orange and by a PCR-based assay. Only two of the patients appeared to be parasitaemic on day 14 and were therefore considered treatment failures. Although both were apparently cured after additional therapy with the same regimen, one had a recurrence 8 months later. Most cases of recent, resurgent malaria in South Korea therefore appear to sensitive to chloroquine.
Adult↗
Tomographic reconstruction of the retina using a confocal scanning laser ophthalmoscope.
Retinal imaging with a confocal scanning laser ophthalmoscope (cSLO) involves scanning a small laser beam over the retina and constructing an image from the reflected light. By applying the confocal principle, tomographic images can be produced. However, the thickness of such slices, when compared with the retinal thickness, is too large to give useful 3D retinal images. In this study an algorithm has been developed which fits a double Gaussian curve to the axial intensity profiles generated from a stack of image slices. The underlying assumption is that the laser light has mainly been reflected by two structures in the retina, the internal limiting membrane and the retinal pigment epithelium. From the fitted curve, topographic images and novel thickness images of the retina can be generated. The technique has been applied to three normal volunteers and seven patients with macular pathology (cystoid macular oedema and macular hole) demonstrating the clinical value of the technique. The improvement in accuracy achieved by using a double rather than a single Gaussian is also demonstrated.
Humans↗
Differential localization and activity of the A- and B-forms of the human progesterone receptor using green fluorescent protein chimeras.
Subcellular localization and transcriptional activity of green fluorescent protein-progesterone receptor A and B chimeras (GFP-PRA and GFP-PRB) were examined in living mammalian cells. Both GFP-PRA and B chimeras were found to be similar in transcriptional activity compared with their non-GFP counterparts. GFP-PRA and PRA were both weakly active, while GFP-PRB and PRB gave a 20- to 40-fold induction using a reporter gene containing the full-length mouse mammary tumor virus long-terminal repeat linked to the luciferase gene (pLTRluc). Using fluorescence microscopy, nuclear/cytoplasmic distributions for the unliganded and hormone activated forms of GFP-PRA and GFP-PRB were characterized. The two forms of the receptor were found to have distinct intracellular distributions; GFP-PRA was found to be more nuclear than GFP-PRB in four cell lines examined. The causes for and implications of this differential localization of the A and B forms of the human PR are discussed.
Animals↗
Cellular localization of alpha3beta1 integrin isoforms in association with myofibrillogenesis during cardiac myocyte development in culture.
The cellular localization of alpha3beta1 integrin isoforms was examined in cultured neonatal myocytes at selected times during development using double immunofluorescence assays. The distribution of alpha3A subunits began as diffuse and patternless, but as the cells matured, the distribution assumed a sarcomeric banding pattern, and alpha3A appeared to be localized in costameres - sarcolemmal regions adjacent to the Z-disks. Alpha-actinin, a component of the Z-disk, was localized in the same intracellular regions. Temporal analysis of the incorporation of the alpha3A subunit and other myofibrillar proteins into sarcomeres revealed that alpha3A was integrated into sarcomeres following incorporation of alpha-actinin and myosin heavy chain (MHC) but prior to that of desmin. This suggests that alpha3A integrins are incorporated into a pre-existing myofibrillar structure, and it is unlikely that alpha3A integrins participate in the initial assembly of myofibrillar proteins. The alpha3B, beta1A and beta1D subunits were also localized in costameres, where they formed alpha3Abeta1A, alpha3Abeta1D and alpha3Bbeta1A heterodimers. The alpha3Bbeta1D heterodimer, however, was not found in cardiac myocytes. The antisera raised against the cytoplasmic domains of alpha3A, alpha3B, beta1A and beta1D caused disruption of sarcomere structure. Thus, the myofibril-extracellular matrix linkages mediated by isoforms of alpha3beta1 integrin may play a crucial role in the stabilization of myofibril assembly and in the maintenance of sarcomere structure. Co-immunoprecipitation experiments revealed that beta1A, but not beta1D, interacts with the Nck signaling protein, suggesting that Nck participates in downstream signaling triggered by beta1A and that the beta1A-mediated signaling pathway is distinct from that of beta1D.
Adaptor Proteins, Signal Transducing↗
Prognostic factors of diffuse proliferative lupus nephritis.
BACKGROUND: Diffuse proliferative lupus nephritis (DPLN) is the most severe form in lupus nephritis. PATIENTS AND METHODS: We retrospectively analyzed 90 DPLN patients who were confirmed by kidney biopsy and treated at least for 12 months to compare the effectiveness of treatment modalities and to investigate the prognostic factors of DPLN. The patients were categorized to intravenous cyclophosphamide pulse (CY) group and oral corticosteroid (with/without cytotoxic drug, PO) group. RESULTS: When the CY group (69 patients) and PO group (21 patients) were compared, there were no differences between two groups in sex, age, histologic chronicity index (CI, 4.55 vs 3.76; CY vs PO, respectively), mortality rate (4.3% vs 0%), remission rate of nephritis (at 3-year 59. 1 % vs 75.5%), renal survival rate (at 5-year 88.0% vs 91.7%) and complications of treatment, but significant differences in the frequency of nephrotic syndrome (66.7% vs 33.3%) and initial azotemia (30.4% vs 0%). histologic activity index (7.14 vs 4.33) and relapse rate (2.9% vs 42.9%). When the remission group (49 patients) and non-remission group (41 patients) were compared, CI, initial renal insufficiency, male sex and the duration of nephritis were the prognostic factors for remission in univariate analysis, and male sex (OR 10.99) and CI (OR 9.89) in multivariate analysis. When the remission group (35 patients) and non-remission (34 patients) group were compared in the CY group, CI was the prognostic factor in univariate analysis, and CI (OR 8.63) and male sex (OR 5.54) in multivariate analysis. The initial renal insufficiency (OR 12.74) and male sex (OR 7.99) were the prognostic factors for renal survival. The renal survival rate was 100% in remission-induced patients. CONCLUSION: We conclude that CI, male sex, initial renal insufficiency were the prognostic factors of DPLN, and treatment with oral corticosteroid could induce remission in patients who had mild histologic and clinical features. Therefore it would be necessary to evaluate the prognostic factors before the selection of treatment modality.
Adult↗
Nephropathy and neuropathy induced by a germanium-containing compound.
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Germanium↗
Simultaneous visualization of the yellow and green forms of the green fluorescent protein in living cells.
In this study we sought to develop a method for the co-localization of proteins in living cells utilizing the enhanced green fluorescent protein (EGFP) and a red-shifted EGFP variant, EYFP (enhanced yellow fluorescent protein). EYFP was expressed as an unsubstituted molecule while EGFP was fused to NF1 (EGFP-NF1), a transcription factor found exclusively in the nucleus. The Leica TCS SP laser scanning confocal microscope was used. This microscope allows the user to monitor the emitted light at defined wavelengths owing to the presence of a monochrometer in the emission light path. pEGFP-NF1 and pEYFP were co-expressed in the same cell and excited with the 476-nm and 488-nm argon laser lines. To separate the EYFP and EGFP fluorescence, EGFP-NF1 emission was recorded between 496 and 505 nm. These wavelengths are on the left shoulder of the EGFP emission peak and exclude most of the EYFP fluorescence. The EYFP emission was followed between 670 and 754 nm, utilizing the tail of EYFP emission that extends well beyond that for EGFP. Under these conditions we obtained excellent discrimination between EYFP fluorescence and EGFP-NF1 emission. These observations demonstrate that EYFP- and EGFP-substituted chimeras can be used for simultaneous detection in living cells.
Animals↗
Partial anatomical and physiological characterization and dissociated cell culture of the nervous system of the marine mollusc Aplysia kurodai.
Snail nervous systems are powerful tools for neurobiological studies as the biophysical properties of the giant neurons and their neural circuits can be examined in relation to specific behaviors of animals. The marine mollusc Aplysia californica is particularly useful for analyzing the components of learning and memory at the molecular and cellular levels. Here we partially examined the nervous systems of two species (A. kurodai and A. juliana) commonly found along the Korean coast in comparison with that of A. californica, one of the American marine snails. A. kurodai appeared to be identical to A. californica in both anatomical and physiological properties of the nervous system. A. juliana could be distinguished from A. californica in certain morphological aspects of the nervous system. The hemolymph either from A. kurodai or from A. juliana was required for effectively elongating neurite outgrowth of A. kurodai neurons in dissociated cell culture. The cultured cells retained neuronal properties such as neurite outgrowth, synapse formation, and generation of action potentials. The sensory cells of A. kurodai in dissociated cultures showed a response to serotonin (5-HT) of spike broadening and enhanced membrane excitability as in intact ganglia. Therefore, the nervous system and dissociated neuronal culture of A. kurodai may be useful for studying learning and memory in the context-of well-defined neural circuits of A. californica.
Action Potentials↗
Sequence-independent inhibition of RNA transcription by DNA dumbbells and other decoys.
DNA dumbbells are stable, short segments of double-stranded DNA with closed nucleotide loops on each end, conferring resistance to exonucleases. Dumbbells may be designed to interact with transcription factors in a sequence-specific manner. The internal based paired sequence of DNA dumbbells in this study contains the X-box, a positive regulatory motif found in all MHC class II DRA promoters. In electrophoretic mobility shift assays (EMSAs), dumbbells and other oligonucleotides ('decoys') with the core X-box sequence were found to compete with the native strand for binding to X-box binding proteins (including RFX1). However, only the X-box dumbbell was capable of forming detectable complexes with such proteins using EMSA. In a model cell system, dumbbells were tested for their ability to block RFX1VP16 activation of a plasmid containing multiple repeats of the X-box linked to the CAT gene. While it appeared that dumbbells could block this activation, the effect was non-specific. This and further evidence suggests an inhibition of transcription, most likely via an interaction with the general transcriptional machinery.
Animals↗
Mutation in the phosphorylation sites of MAP kinase blocks learning-related internalization of apCAM in Aplysia sensory neurons.
The synaptic growth that accompanies 5-HT-induced long-term facilitation of the sensory to motor neuron connection in Aplysia is associated with the internalization of apCAM at the surface membrane of the sensory neuron. We have now used epitope tags to examine the fate of each of the two apCAM isoforms (membrane bound and GPI-linked) and find that only the transmembrane form is internalized. This internalization can be blocked by overexpression of transmembrane constructs with a single point mutation in the two MAPK consensus sites, as well as by injection of a specific MAPK antagonist into sensory neurons. These data suggest MAPK phosphorylation at the membrane is important for the internalization of apCAMs and, thus, may represent an early regulatory step in the growth of new synaptic connections that accompanies long-term facilitation.
Animals↗
Control of C. elegans larval development by neuronal expression of a TGF-beta homolog.
The Caenorhabditis elegans dauer larva is specialized for dispersal without growth and is formed under conditions of overcrowding and limited food. The daf-7 gene, required for transducing environmental cues that support continuous development with plentiful food, encodes a transforming growth factor-beta (TGF-beta) superfamily member. A daf-7 reporter construct is expressed in the ASI chemosensory neurons. Dauer-inducing pheromone inhibits daf-7 expression and promotes dauer formation, whereas food reactivates daf-7 expression and promotes recovery from the dauer state. When the food/pheromone ratio is high, the level of daf-7 mRNA peaks during the L1 larval stage, when commitment to non-dauer development is made.
Amino Acid Sequence↗
Colour Doppler imaging in giant cell (temporal) arteritis: serial examination and comparison with non-arteritic anterior ischaemic optic neuropathy.
The ophthalmological manifestations of giant cell arteritis (GCA) present a difficult diagnostic and management problem to the ophthalmologist. The orbital circulation is frequently involved in the disease process. The effects of GCA on orbital blood flow assessed by colour Doppler imaging (CDI) were investigated in this study. Serial CDI examinations of the orbital blood vessels were performed (at presentation, 2 days, 1 week and at 1 month) on 7 patients with GCA. CDI examination at presentation was also performed on 4 patients with non-arteritic anterior ischaemic optic neuropathy (AION) for comparison. Blood flow could not be detected in up to three arteries in the affected (ipsilateral) orbit of 6 GCA patients at presentation. Five of these patients were also found to have undetectable blood flow in the posterior ciliary arteries of the contralateral orbit. Serial CDI examination revealed blood flow alterations in arteritic patients despite treatment. Return of blood flow to normal was slow, and related to the clinical features. By contrast, only 1 of the patients with non-arteritic AION showed undetectable blood flow in a posterior ciliary artery. GCA leads to widespread and prolonged alterations in orbital blood flow. CDI allows the detection and monitoring of such alterations in orbital blood flow, which correlate with the clinical features of GCA. Serial CDI examinations in GCA may be used to aid management decisions.
Aged↗
A simple clinical method to measure the optic disc size in glaucoma.
PURPOSE: The cup-to-disc ratio is a widely used clinical measure of optic nerve damage in the management of glaucoma patients and those suspected of having glaucoma. Knowledge of the optic disc size allows for a better assessment of the clinical significance of the cup-to-disc ratio. In this study, two optical methods-slit-lamp biomicroscopy and confocal scanning laser ophthalmoscopy-were used to measure the vertical disc diameter as an indirect measure of optic disc size. The aim was to provide a simple and clinically useful examination technique in the management of glaucoma. METHODS: The vertical optic disc diameter was measured with aspheric lenses (Volk 60, 78, and 90 D, and Nikon 60 and 90 D) using slit-lamp biomicroscopy in 25 emmetropic normal volunteers. The average of three readings was determined for each of the lenses and the measurements were correlated with the magnification-corrected diameter measured with the Heidelberg Retina Tomograph. RESULTS: The mean vertical disc diameter of the group, as measured with the Heidelberg Retina Tomograph, was 1.81 +/- 0.18 mm. Results obtained with the lower-power lenses correlated best with the Heidelberg Retina Tomograph measurements (for example, Volk 60 D: r = 0.80, p = 0.0001, 95% confidence interval 1.76-1.85 mm), whereas the 90-D correlation was the weakest (for example, Volk 90 D: r = 0.59. p = 0.002, 95% confidence interval 1.75-1.87 mm). With the Volk 60-D lens, the "best fit" equation for estimating disc diameter, in millimetres, is Y = 0.85X + 0.06, where Y is the Heidelberg Retina Tomograph value and X is the slit-lamp biomicroscopy measurement. CONCLUSION: Using these formulae, the clinician is able to estimate the optic disc diameter with sufficient accuracy to allow clinical decisions to be made in the evaluation of patients with glaucoma, without recourse to expensive technology.
Adult↗
Gastric stump carcinoma: a surgical challenge.
Gastric stump carcinoma is a carcinoma arising in the stomach remnant following previous gastric resection. It is a distinct disease entity with its unique aetiology and pathogenesis. We report 3 cases of gastric stump carcinoma encountered in the department over the past 5 years and review current literature pertaining to its clinical presentation, aetiology, pathogenesis, treatment strategy and the role of screening endoscopy. The disease is characterised by its late presentation and dismal prognosis and will continue to pose a surgical challenge in the years to come.
Adenocarcinoma↗
The Abrams-Griffiths nomogram.
The treatment of benign prostatic hyperplasia and the definition of bladder-outlet obstruction has preoccupied urologists and researchers in recent years. Bladder-outlet obstruction can be defined only by pressure-flow measurement. Various methods of analysis of pressure-flow data have been proposed. The Abrams-Griffiths nomogram is an easy method of classifying these data to distinguish between the presence or absence of obstruction. Using the values for the maximal flow and the corresponding voiding detrusor pressure a point can be plotted on the nomogram that determines whether the bladder outlet is obstructed, unobstructed, or equivocally obstructed. For those that fall in the equivocal zone, further criteria for the mean slope of the pressure-flow plot and the minimal voiding detrusor pressure are used to determine whether there is obstruction or not. The nomogram's prognostic value in predicting the outcome of prostatectomy has been studied and found to be excellent. The Abrams-Griffiths nomogram can be modified by assigning an Abrams-Griffiths number to each set of pressure-flow data. This number is easy to calculate and use and gives a continuous variable that can be used to evaluate the effects of therapy. Although the Abrams-Griffiths nomogram and number are somewhat simplistic, none of the more complex methods of pressure-flow analysis have been shown to be better predictors of treatment outcome to date.
Data Interpretation, Statistical↗