Biomedical subjects
S Cho
Publications and source records attributed to S Cho.
Graves' disease presenting as elephantiasic pretibial myxedema and nodules of the hands.
A 67-year-old man presented with a 2-year history of asymptomatic, firm, multiple nodules and plaques and cerebriform hypertrophy of both lower legs and feet, and well-defined, skin-colored, firm nodules and tumors on both hands. He had been diagnosed as having Graves' disease 3 years previously, and had been treated with 10 mg of methimazole and 100 microg of thyroxin (T4) daily for 2 years. Physical examination revealed nonpitting edema, flesh-colored to erythematous, firm, confluent, polypoid nodules and fissured plaques extending from the shins to the dorsa of both feet (Fig. 1), and round to oval, firm, skin-colored, walnut-to-egg-sized tumors on all 10 fingers and the ulnar side of the dorsum of the right hand (Fig. 2). The thyroid gland was diffusely enlarged; however, there was no exophthalmos, and extraocular movements were normal. There was no weight loss, loss of appetite, tremor, heat intolerance, diarrhea, or fatigue. On laboratory evaluation, thyroid-stimulating hormone (TSH) had a markedly low titer of < 0.05 microU/mL (normal: 0.4-5.0), and the TSH receptor antibody was extremely high at 73.8% (normal: < 15%). Serum free triiodothyronine (T3), T4, antimicrosome, and antithyroglobulin antibodies were normal or negative. Skin biopsy samples from the shin and hand disclosed extensive mucin deposition throughout the dermis.
Treatment of "Cyrano" angioma with pulsed dye laser.
BACKGROUND: Hemangiomas of the nasal tip, the so-called Cyrano nose, are often deep, disfiguring, and persistent. OBJECTIVE: To evaluate the effect of treatment with pulsed dye laser on Cyrano nose. METHODS: A 3-month-old boy with hemangioma of the nasal tip of 1-months duration underwent six sessions of pulsed dye laser treatment with a 7 mm collimated beam at fluences of 5.75-6.5 J/cm2, 6 weeks apart. RESULTS: Initial improvement was noted after two treatments, and the lesion showed a marked reduction in size and improvement in color over a total treatment period of 9 months. CONCLUSION: Treatment with the 585 nm pulsed dye laser should be considered in the management of infants with mild to moderate degrees of nasal tip hemangiomas since it effectively reduces the lesions with minimal adverse effects.
Role of palmitoyl-protein thioesterase in cell death: implications for infantile neuronal ceroid lipofuscinosis.
Infantile neuronal ceroid lipofuscinosis (INCL) is a childhood neurodegenerative disease caused by the selective death of cortical and retinal neurons as the result of an inherited palmitoyl-protein thioesterase 1 (PPT1) deficiency. Neuronal death is common to many lysosomal storage diseases but it occurs very early in INCL and we show here that inhibition of PPT1 increases the susceptibility of these cells to apoptotic cell death. Thus transient transfection of LA-N-5 neuroblastoma cells with a reverse-oriented (antisense) PPT1 (AS-PPT1) reduced PPT1 enzyme activity (as measured by an in vitro assay) and increased the susceptibility to apoptosis induced by C2 ceramide. Similarly, inhibition of PPT1 with a synthetic inhibitor (AcG-palmitoyl diaminoproprionate-VKIKK) (DAP1) (100 microM) increased the susceptibility of the cells to apoptosis induced by either C2-ceramide or etoposide and Adriamycin (doxorubicin), common chemotherapeutic agents used in the treatment of solid tumours. In contrast, overexpression of PPT1 led to increased resistance to cell death induced by these drugs.
Human aldehyde dehydrogenase catalytic activity and structural interactions with coenzyme analogs.
K(m) and V(max) values for 10 coenzyme analogs never previously studied with any aldehyde dehydrogenase and NADP(+) were compared with those for NAD(+) for three human aldehyde dehydrogenases (EC 1.2.1.3); the cytoplasmic E1 (the product of the aldh1 gene), the mitochondrial E2 (the product of the aldh2 gene) and the cytoplasmic E3 (the product of the aldh9 gene) isozymes. Structural information on changes in coenzyme-protein interactions were obtained via molecular dynamics (MD) studies with the E2 isozyme and quantum mechanical (QM) calculations were used to study changes in charge distribution of the pyridine ring and relative free energies of solvation of the purine ring in the analogs. E1 showed the broadest substrate specificity and was the only isozyme subject to substrate inhibition, both of which are suggested to be due to the two coenzyme conformations observed previously in the sheep crystal structure. NADP(+) selectivity is indicated to be influenced by Glu195 in E1 and E2. Substitutions in the purine ring affected K(m) but not V(max), with the changes in K(m) being dominated by the hydrophobicity of the purine ring as indicted by the QM calculations. Substitutions in the pyridine ring sometimes rendered the coenzymes inactive, with no consistent pattern observed for the three coenzymes. Structural analysis of the coenzyme analog-E2 MD simulations revealed different structural perturbations of the surrounding active site, though interactions with Asn169 and Glu399 were preserved in all cases.
Specification of germ cell fates by FOG-3 has been conserved during nematode evolution.
Rapid changes in sexual traits are ubiquitous in evolution. To analyze this phenomenon, we are studying species of the genus Caenorhabditis. These animals use one of two different mating systems-male/hermaphroditic, like the model organism Caenorhabditis elegans, or male/female, like C. remanei. Since hermaphrodites are essentially females that produce sperm for self-fertilization, elucidating the control of cell fate in the germ line in each species could provide the key to understanding how these mating systems evolved. In C. elegans, FOG-3 is required to specify that germ cells become sperm. Thus, we cloned its homologs from both C. remanei and C. briggsae. Each species produces a single homolog of FOG-3, and RNA-mediated interference indicates that FOG-3 functions in each species to specify that germ cells develop as sperm rather than as oocytes. What factors account for the different mating systems? Northern analyses and RT-PCR data reveal that the expression of fog-3 is always correlated with spermatogenesis. Since the promoters for all three fog-3 genes contain binding sites for the transcription factor TRA-1A and are capable of driving expression of fog-3 in C. elegans hermaphrodites, we propose that alterations in the upstream sex-determination pathway, perhaps acting through TRA-1A, allow spermatogenesis in C. elegans and C. briggsae XX larvae but not in C. remanei.
Early c-Fos induction after cerebral ischemia: a possible neuroprotective role.
The role of c-Fos in neurodegeneration or neuroprotection after cerebral ischemia is controversial. To investigate whether early c-Fos induction after ischemia is associated with neuroprotection, rats were subjected to 10 minutes of transient forebrain ischemia and c-Fos expression was examined. Resistant dentate granule cells and neurons in CA2-4 displayed more robust immunoreactivity than vulnerable neurons in the CA1 region of hippocampus during early hours of reperfusion. By 6 hours after reperfusion, c-Fos immunoreactivity was greatly diminished in all areas of the hippocampus. Administration of N-acetyl-O-methyldopamine (NAMDA), a compound previously shown to protect CA1 neurons against ischemia, increased c-Fos immunoreactivity in the CA1 vulnerable region at 6 hours after ischemia and protected SK-N-BE(2)C neurons from oxygen glucose deprivation. Further in vitro study showed that NAMDA potentiated phorbol-12 myristate-13 acetate (PMA)-induced c-Fos expression, AP1 binding activity, and late gene expression determined by chloramphenicol acetyltransferase (CAT) activity from AP1 containing tyrosine hydroxylase promoter-CAT fusion gene in SK-N-BE(2)C neurons. In vivo and in vitro results showed that a neuroprotectant, NAMDA, in concert with another stimulus (for example, ischemia or PMA) up-regulates c-Fos expression and suggested that the early rise of NAMDA-induced c-Fos expression in vulnerable CA1 neurons may account for neuroprotection by means of up-regulating late gene expression for survival.
Interim assessment of a community intervention to improve breast and cervical cancer screening among Korean American women.
Breast and cervical cancer screening practices are suboptimal among Korean American women. A community intervention program was launched in 1996 to improve breast and cervical cancer screening among Korean American women in Alameda County, California. After 18 months, interim program assessment revealed that mammograms improved, but Pap smears, breast self-examinations, and clinical breast examinations did not change significantly. However, results were similar for the control county probably because the program was not implemented fully. Several strategies for improving program implementation are discussed including recommendations for researchers planning community intervention projects.
Clinicohistopathologic comparison of adult type and juvenile type xanthogranulomas in Korea.
Xanthogranuloma (XG) is an uncommon benign disorder characterized by solitary or multiple yellow-red papulonodules on the skin, and occasionally, in other organs. It is predominantly a disease of infancy or early childhood, although adults may rarely be affected. To compare the clinicohistopathological featues of juvenile-type xanthogranulomas UXGs) and adult-type xanthogranulomas (AXGs) (>14 years) in Korea, 30 cases of JXGs and 15 cases of AXGs were compared clinically and histopathologically. Except for the fact AXGs were more often solitary and larger and showed neither other associated systemic diseases nor spontaneous regression, the clinical features such as color, mean number, or site of the lesions in AXGs were not statistically different from JXGs. Histologically, AXCs were not significantly different in amounts of foamy cells, giant cells including Touton cells, and inflammatory cells, although subcutaneous involvement was seen only in the two infant cases. In conclusion, in contrast to AXGs, JXGs need special attention to accompanying systemic diseases and do not need excisional procedures, considering their frequent spontaneous regression.
Chronic tophaceous gout presenting as hyperpigmented nodules in the limbs of a patient with coexisting psoriasis.
We describe a 53-year-old male renal transplant recipient with hypertension and triglyceridemia, who showed rare manifestations of gout presenting as brownish nodules on the arms and legs as well as chronic tophaceous gouty arthritis of the hands and feet mimicking rheumatoid arthritis, in association with subsequently developed psoriasis of the palms. In elderly Asian men, hypertension and renal insufficiency may be risk factors predisposing to the development of multiple hyperpigmented nodules of tophi in the more proximal extremities.
Selective loss of natural killer T cells by apoptosis following infection with lymphocytic choriomeningitis virus.
Natural killer T (NKT) cells, a unique subpopulation of T cells, coexpress markers also present on NK cells and recognize the major histocompatibility complex class I-like CD1d1 molecule. We studied the effect of an acute virus infection on NKT cells. Mice were infected with the nonhepatotropic Armstrong strain of lymphocytic choriomeningitis virus (LCMV), and at various times postinfection, mononuclear cells from the liver, peritoneum, and spleen were isolated. It was found that within 2 to 3 days, there was a selective loss of NKT cells from the liver with an apparent rapid recovery within 8 to 14 days. There was no increase in peritoneal or splenic NKT cells, indicating that NKT cells did not traffic to these tissues. This loss of NKT cells was independent of gamma interferon (IFN-gamma) and interleukin 12 (IL-12) production, but did occur in mice treated with poly(I-C), a classical inducer of IFN-alpha/beta. The reduction in NKT cells was CD28 and fas/fasL independent and occurred via apoptosis. It was not observed in LCMV-infected DNA fragmentation factor 45-deficient mice, and an increase in active caspase 3-specific staining was found in liver NKT cells from LCMV-infected and poly(I-C)-treated mice compared to uninfected wild-type mice. Interestingly, it was also found that liver NKT cells from LCMV-infected mice were themselves infected. These results suggest that the loss of NKT cells following an acute LCMV infection could be due to the induction of IFN-alpha/beta resulting in NKT-cell apoptosis and is important for the host's immune response to LCMV.
Modelling and prediction for chaotic fir laser attractor using rational function neural network.
Many real-world systems such as irregular ECG signal, volatility of currency exchange rate and heated fluid reaction exhibit highly complex nonlinear characteristic known as chaos. These chaotic systems cannot be retreated satisfactorily using linear system theory due to its high dimensionality and irregularity. This research focuses on prediction and modelling of chaotic FIR (Far InfraRed) laser system for which the underlying equations are not given. This paper proposed a method for prediction and modelling a chaotic FIR laser time series using rational function neural network. Three network architectures, TDNN (Time Delayed Neural Network), RBF (radial basis function) network and the RF (rational function) network, are also presented. Comparisons between these networks performance show the improvements introduced by the RF network in terms of a decrement in network complexity and better ability of predictability.
Neural network based automatic diagnosis of children with brain dysfunction.
This paper proposes the use of multilayer perceptron for brain dysfunction diagnosis. The performance of MLP was better than that of Discriminant Analysis and Decision Tree classifiers, with an 85% accuracy rate in an experimental test involving 332 subjects. In addition, the neural network employing Bayesian learning was able to identify the most important input variable. These two results demonstrate that the neural network can be effectively used in the diagnosis of children with brain dysfunction.
Regulation of gonadotropin subunit gene transcription by gonadotropin-releasing hormone: measurement of primary transcript ribonucleic acids by quantitative reverse transcription-polymerase chain reaction assays.
GnRH regulates the synthesis and secretion of the pituitary gonadotropins LH and FSH. One of the actions of GnRH on the gonadotropin subunit genes (alpha, LHbeta, and FSHbeta) is the regulation of transcription [messenger RNA (mRNA) synthesis]. Gonadotropin subunit transcription rates increase after gonadectomy and following exogenous GnRH pulses. However, prior studies of subunit mRNA synthesis were limited by the available methodology that did not allow simultaneous measurement of gene transcription and mature mRNA concentrations. The purpose of the current studies was to: 1) develop a reliable and sensitive method for assessing transcription rates by measuring gonadotropin subunit primary transcript RNAs (PT, RNA before intron splicing); 2) investigate the PT responses to GnRH following castration or exogenous GnRH pulses; 3) characterize the half-disappearance time for the three PT species after GnRH withdrawal; and 4) correlate changes in PT concentration with steady-state gonadotropin subunit mRNA levels measured in the same pituitary RNA samples. Using oligonucleotide primers that flanked intron-exon boundaries, quantitative RT-PCR assays for each subunit PT species were developed. These assays require only ng amounts of RNA to measure each gonadotropin subunit PT and allow us to measure both PTs and steady-state mRNAs in a single pituitary RNA sample. Primary transcript concentrations in intact male rats showed a relative abundance of alpha > LHbeta congruent with FSHbeta, similar to the relationship found previously for mRNA levels. Additionally, each PT species was only 1-2% as abundant as the corresponding mRNA. One week after castration, gonadotropin subunit PT levels were increased (alpha: 3-fold, LHbeta: 6-fold, and FSHbeta: 3-fold) in a pattern similar to subunit mRNAs. Administration of GnRH antagonist to 7-day castrate male rats resulted in a rapid decline in PT concentrations with a half-disappearance time of 2.7 h for LHbeta and 0.8 h for FSHbeta, significantly faster than earlier measurements of the half-disappearance time for mature mRNA. Finally, in a GnRH-deficient male rat model, LHbeta and FSHbeta PT concentrations increased 4- to 6-fold 5 min after a GnRH pulse and then declined toward levels seen in control animals. These data indicate that the effects of GnRH on subunit gene transcription are an important determinant of gonadotropin regulation. The appearance and disappearance of PT RNA occurs more rapidly than changes in mature mRNA. Additionally, concentrations are elevated in long term castrates, and following an exogenous GnRH pulse the transcriptional burst is rapid and brief.
Detection of inducible nitric oxide synthase- and nitrotyrosine-positive cells in the lesions of pericarditis induced by porcine enterovirus serotype 3 infection.
The expression of inducible nitric oxide synthase (iNOS), an enzyme that produces nitric oxide, was examined in the hearts of pigs infected with porcine enterovirus serotype 3 (PEV3). Piglets orally infected with PEV3 developed tremors and paralysis 3-7 days post-infection. Affected animals had pericarditis and myocarditis. There were fibrin and inflammatory cell infiltrates (macrophages and neutrophils) in the pericardial sac and myocardium. Immunohistochemically, the majority of inflammatory cells in the pericardial sac were positive for iNOS and nitrotyrosine, an end product of nitric oxide. These results suggest that iNOS is upregulated in the pericardial lesion, and that increased nitric oxide production plays an important role in the development of PEV3-induced pericarditis and myocarditis.
Immunohistochemical analysis of CD44s and CD44v6 in endometriosis and adenomyosis : comparison with normal, hyperplastic, and malignant endometrium.
The expression patterns of CD44s and CD44v6 were immunohistochemically compared with those of normal, hyperplastic and malignant endometrium. In normal endometria (n=37), endometrioses (n=46) and adenomyoses (n=20), the surface and glandular epithelial cells were negative for CD44s and CD44v6 in a proliferative pattern and positive in a secretory pattern, whereas the stroma was only positive for CD44s in both proliferative and secretory patterns. The endometrial hyperplasia (4 simple and 9 complex) had the identical patterns with normal proliferative phase of endometrium. Only one case showing complex hyperplasia with atypia was focally positive for CD44s and CD44v6 in glandular epithelia. CD44s and CD44v6 were positive in all endometrial adenocarcinomas (13), except one CD44s-negative case. In summary, the expressions of CD44s and CD44v6 in endometriosis and adenomyosis recapitulated those of normal cyclic endometrium. The expression patterns in endometrial hyperplasia were similar to those in normal proliferative endometrium, whereas the endometrial adenocarcinoma showed abnormal expressions for CD44s and CD44v6. Thus it was considered that the ectopic endometrium in endometriosis and adenomyosis was not aberrant as in endometrial carcinoma on the aspects of immunohistochemical expressions of CD44s and CD44v6.
High dose hook effect in serum total and free prostate specific antigen in a patient with metastatic prostate cancer.
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[Alpha2 agonists and their clinical use in anesthesia].
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