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Biomedical subjects

S Cho

Publications and source records attributed to S Cho.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of clonidine on human middle cerebral artery flow velocity and cerebrovascular CO2 response during sevoflurane anesthesia.

The present study was designed to evaluate the effects of clonidine on human middle cerebral artery flow velocity and the cerebrovascular CO2 response during sevoflurane anesthesia using transcranial Doppler ultrasonography. The subjects were nine awake volunteers (group A) and 18 patients receiving oral preanesthetic medication of clonidine, 3-4 mcg/kg, (group C), or placebo (group S). In groups C and S, anesthesia was induced with inhalation of sevoflurane-nitrous oxide. After tracheal intubation, anesthesia was maintained with 2% end-tidal sevoflurane alone. In group A, each volunteer wore a nose clip and breathed through a mouthpiece using a Mapleson D breathing system. The time-mean middle cerebral artery flow velocity (Vmca) was measured during hypocapnia, normocapnia, and hypercapnia. In groups S and C, the Vmca values were significantly lower than those of group A at each PaCO2 level. The Vmca value of group C was significantly lower than that of group S in hypercapnia, but not in hypocapnia or normocapnia. The CO2 response slope of group C was significantly lower than those of groups A and S. The results indicate that clonidine, administered as an oral preanesthetic medication, reduces Vmca in hypercapnia but not in hypocapnia or normocapnia, and reduces the cerebrovascular CO2 response during sevoflurane anesthesia.

Adrenergic alpha-Agonists↗
PubMed1999

Clinical and histopathological characteristics of basal cell carcinoma in Korean patients.

Seventy-eight Korean patients with basal cell carcinoma (BCC) between 1984 and 1998 were retrospectively examined at Ewha Womans University Tongdaemun Hospital, Seoul, Korea. We analyzed the annual incidence, age and sex distribution, site of the lesions, clinical appearance, including the proportion of clinically pigmented tumors, modalities of treatment, incidence of recurrence and metastasis of the tumors, the histopathological patterns, and whether solar elastosis, microscopic pigmentation, or adamantinoid feature were associated. The male-to-female ratio was 0.902, and the average age of the patients at first examination was 58.2 years. Eighty percent of the tumors occurred on the head and neck, most commonly on the nose (26.9%), followed by the cheek, eyelid, and upper lip. Ulcerated nodules were the most common clinical presentation. Clinically, 55% of the tumors were pigmented. Six tumors recurred; none metastasized. Surgical excision was the most common modality of treatment. The most frequent histopathological pattern was the solid type (60.3%), followed by the superficial (11.5%) and fibrosing (9.0%) types. The occurrence of the superficial type was significantly associated with truncal lesions (p < 0.001). Solar elastosis was present in 62.1% of the tumors on the head and neck, compared with 8.3% in those of the trunk and limbs (p < 0.001), indicating the significance of sun exposure in the pathogenesis of BCC on exposed areas. Microscopic pigmentation was seen in 69.2% of the tumors. The focal adamantinoid feature was found in 14.1%, which is much higher than the previously reported incidence.

Adolescent↗
PubMed1999

Growth of newborn, term infants fed soy formulas for 1 year.

Few studies have measured long-term growth in infants fed soy protein-based formulas. The effect of nucleotide (NT) supplementation of soy protein-based infant formulas on growth is unknown. Growth was therefore evaluated in healthy term infants fed a soy protein-based formula (SOY; n = 73), SOY with added NT (72 mg added NT/L) at human milk (HM) levels (SOYN, n = 73), or mixed feeding (MF, n = 67) in a randomized, masked, parallel 1-year feeding study. The MF group (a nonrandomized reference group) was fed HM exclusively from birth to 2 months of age followed by HM and/or a standard milk-based formula (Similac with Iron with no supplemental NTs) to 1 year of age. Results indicated that growth (weight, length, and head circumference) was normal and comparable among the three groups. All three groups had similar plasma albumin (at 2 months of age) and hemoglobin levels (at 12 months of age). Thus, this study demonstrated similar growth in the first year of life among infants fed MF feeding or soy formula with or without supplemental NTs.

Age Factors↗
PubMed1999

Development of guidelines for treatment of children with phenylketonuria: report of a meeting at the National Institute of Child Health and Human Development held August 15, 1995, National Institutes of Health, Bethesda, Maryland.

OBJECTIVE: To convene a small group of experts in diagnosis and management of PKU to discuss the following issues: the Subject Review of PKU management being performed by the American Academy of Pediatrics (AAP) Committee on Genetics (COG), the published British guidelines on PKU management, and the feasibility, suitability, and mechanism of developing PKU management guidelines for the United States. METHODS: A 1-day meeting was held at the National Institutes of Health under the auspices of National Institute of Child Health and Human Development, convening experts in PKU diagnosis and management and members of the AAP/COG. RESULTS: The group reviewed the published reports of outcomes of treatment of PKU and the British guidelines that were developed based on those data. It also reviewed the results of surveys of directors of clinics that manage PKU, parents of children with PKU, and young adults with PKU. CONCLUSION: The group supported the efforts of the AAP/COG to perform this review of PKU management. The group concluded that significant issues need to be resolved to provide sufficient information to establish US guidelines for PKU management. The establishment of such guidelines is an important next step in PKU management in the United States.

Adult↗
PubMed1999

Management of phenylketonuria for optimal outcome: a review of guidelines for phenylketonuria management and a report of surveys of parents, patients, and clinic directors.

OBJECTIVE: The development of guidelines for phenylketonuria (PKU) management in the United Kingdom has resulted in much discussion in the community of parents and PKU clinics and parents have asked why the United States does not have such guidelines. The objective of this report is to discuss PKU management in the United States, the British guidelines on PKU management, and the feasibility, suitability, and mechanism of developing PKU management guidelines in the United States. METHODS: Members of the American Academy of Pediatrics (AAP) Committee on Genetics (COG) reviewed the literature and conducted surveys of parents of children with PKU, young adults with PKU, and directors of PKU clinics in the United States. A meeting was held at the National Institute of Child Health and Human Development to review the AAP/COG efforts at reviewing the status of PKU management and guideline development in the United States. RESULTS: The British guidelines are more stringent than the PKU management practices in many parts of the United States. Evidence exists that stricter management improves developmental outcome. The parents who responded to the surveys indicated willingness to comply with more stringent dietary management if that would improve outcome. They also identified problems that make such management difficult. The clinic directors supported the timeliness of the review. Some had begun a trend toward more stringent control of blood phenylalanine concentrations, at least in the first 4 years of life. CONCLUSION: The AAP Committee on Genetics will complete its subject review of the management of PKU. Guidelines for care of PKU in the United States probably would look quite similar to the existing guidelines in other countries. The parents surveyed supported more stringent PKU management, but information from a broader distribution of parents would provide a more representative view. The status of the US health care system creates problems for improved PKU management in the United States that do not exist in the countries already following stricter guidelines.

Adult↗
PubMed1999

[Effectiveness of low dose continuous infusion of alpha-hANP from the start of cardiopulmonary bypass].

In this study, we used alpha-human atrial natriuretic peptide (hANP) from staring on cardiopulmonary bypass and evaluated for the hemodynamics, ANP, renin activity, aldosterone, urine volume, glomerular filtration rate (GFR) and so on. The hANP decreased renin activity, aldosterone, systemic vascular resistance and increased urine volume, GFR and use of furosemide and KCL were decreased. We concluded that hANP was effective for hemodynamics, renal function and hormonal release on intra and post-operation in cardiac surgery, and low dose continuous infusion of alpha-hANP from staring on cardiopulmonary bypass will be expected as a newly application.

Aldosterone↗
PubMed1999

[Two-step ultra high-dose chemotherapy with peripheral blood stem cell autotransplantation for refractory testicular cancer: a case report].

A 35-year-old male had advanced nonseminomatous germ cell tumor (stage IIIC, embryonal cell carcinoma) which proved refractory to conventional PVB combined chemotherapy. He was then treated with an ultra high-dose chemotherapy consisting of carboplatin (1.5 g/m2) and etoposide (1.3 g/m2), followed by the transplantation of peripheral blood stem cells (PBSCT) with a total of 1.9 x 10(5)/kg granulocyte colony-forming cells (CFU-GM). Because he developed lung metastasis, escalated doses of carboplatin (2.0 g/m2), and etoposide (1.8 g/m2) combined with cyclophosphamide (7.0 g/m2) were given with peripheral blood stem cell transplant of 3.2 x 10(5)/kg CFU-GM. He has remained free of any recurrence without maintenance therapy.

Adult↗
PubMed1999

Perifollicular fibroma.

Perifollicular fibroma(PFF) is a rare cutaneous hamartoma that shows differentiation in the connective tissue sheath of the hair follicle. It may be single (congenital or acquired) or multiple (late onset). We report a 14-year-old Korean boy with a congenital solitary PFF on the face, which supports the nevoid concept of origin rather than a reactive response to injury.

Adolescent↗
PubMed1998

Glutathione downregulates the phosphorylation of I kappa B: autoloop regulation of the NF-kappa B-mediated expression of NF-kappa B subunits by TNF-alpha in mouse vascular endothelial cells.

Nuclear factor-kappa B (NF-kappa B) regulates gene expression upon immune and inflammatory responses. It has been demonstrated that redox regulation by thiols is involved in the signal-transduction cascade. In this study, we examined the effect of glutathione (GSH) on the NF-kappa B activity and the expression of NF-kappa B subunits induced by tumor necrosis factor-alpha (TNF-alpha) using mouse vascular endothelial cells. GSH inhibited the serine phosphorylation of I kappa B-alpha by TNF-alpha, leading to the downregulation of NF-kappa B-DNA binding activity followed by decreased expression of p65/p50 and I kappa B mRNAs. The regulation of the autoregulatory loop for the NF-kappa B activation and the expression of NF-kappa B subunits may be important in endothelial cells in response to cytokines.

Animals↗
PubMed1998

Gonadotropin-releasing hormone (GnRH) gene regulation by N-methyl-D-aspartic acid in GT1-1 neuronal cells: differential involvement of c-fos and c-jun protooncogenes.

The present study examined the regulatory mechanisms of GnRH gene expression by N-methyl-d-aspartic acid (NMDA) in immortalized hypothalamic GnRH neurons (GT1-1 cells). NMDA (100 microM) stimulated GnRH mRNA levels transiently at 2 h after treatment. Dose-response experiment showed that there was a biphasic action of NMDA on GnRH mRNA levels: GnRH mRNA levels were increased by NMDA at lower concentrations (10 and 100 microM), but not at higher concentrations (1 and 10 mM). NMDA (100 microM)-induced GnRH mRNA levels were efficiently blocked by pre-treatment with NMDA receptor antagonists, MK-801 and AP-5. We next examined the signal transduction pathways involved in NMDA-induced GnRH gene expression based on previous findings that NMDA signal propagates into the cell through Ca2+ and nitric oxide (NO) pathways in many neurons. While ionomycin, a Ca2+ ionopore, application failed to alter GnRH gene expression, treatment of GT1-1 cells with sodium nitroprusside (SNP), an NO donor, increased GnRH gene expression with a similar time course to NMDA treatment. Moreover, application of GT1-1 cells with nitric oxide synthase (NOS) inhibitors (l-NAME, d-NAME, and NA) prior to NMDA treatment, inhibited NMDA-induced GnRH gene expression. These results indicate that the effect of NMDA is mediated by the NO signalling cascade. The mouse GnRH promoter activity was also increased by NMDA at low concentration (100 microM), but not at high concentration (1 microM), confirming the biphasic action of NMDA on GnRH mRNA levels. Since NMDA (100 microM) and SNP (1 microM) markedly induced c-jun expression, but not c-fos expression, we hypothesized that Jun activation is responsible for the transcriptional activation of GnRH gene expression. To examine this, we performed two different experiments. Treatment of NMDA greatly increased the activity of heterologous promoter of Fos/Jun responsive sequence (-187/-69) from the mouse GnRH promoter fused to hsv-tk minimal promoter. Moreover, overexpression of c-jun induced GnRH promoter activity, while c-fos overexpression decreased GnRH promoter activity. Taken together, this study indicates that NMDA regulates GnRH gene expression in GT1-1 cells through the NO-Jun signal transduction pathway.

Animals↗
PubMed1998

Linkage between oligomerization and DNA binding in Drosophila doublesex proteins.

The doublesex gene of Drosophila melanogaster encodes DSXM protein in males and DSXF protein in females. Dimers of each protein bind a DNA site from which DSXM represses and DSXF activates transcription. Amino acids 1-397 are identical between the proteins and include a domain (DBD) for both DNA binding and protein oligomerization. The remaining nonhomologous and therefore sex-specific C-termini include an essential part of a second oligomerization domain. We have used mobility shift assays to investigate the effects these three oligomerization domains (DBD and two sex-specific) have on DSX dimerization and DNA binding. The intrinsic DNA binding affinities of DSXM and DSXF dimers are indistinguishable from each other (0.17 +/- 0.04 nM) and slightly lower than that of DBD dimers (0.48 nM). In contrast, the dimerization dissociation constants of DSXM (0.05 +/- 0.02 nM) and DSXF (0.16 +/- 0.05 nM) are slightly different, but 4 orders of magnitude lower than that of DBD (430 nM). Thus sequences outside of DBD, presumably the sex-specific oligomerization domains, have substantial effects on apparent DNA binding affinity through thermodynamically linked effects on dimerization of full-length proteins. Further, when two DNA binding sites are adjacent, DBD dimers show no binding cooperativity, whereas full-length dimers bind with 2-fold different cooperativity (DSXF, k12 = 2.6; DSXM, k12 = 5.4). This suggests that the sex-specific domains may have a second effect on DNA binding, namely, an effect on binding cooperativity that depends on the number and arrangement of DNA sites.

Animals↗
PubMed1998

Molecular cloning of multiple isoforms of synaptojanin 2 and assignment of the gene to mouse chromosome 17A2-3.1.

Synaptojanin 2 is an inositol polyphosphate 5'-phosphatase that appears to be regulated by alternative splicing. By screening mouse cDNA libraries derived from either mouse day 16 embryo or adult liver, we have identified additional synaptojanin 2 cDNAs that represent six new isoforms of the protein. This finding, together with other reports, indicates the presence of eight isoforms of synaptojanin 2. Sequence analysis of our cDNA clones suggests that there are at least two putative initiation sites and at least six different sequences coding for the carboxyl-terminus of the molecule. In addition, we have mapped synaptojanin 2 to mouse chromosome 17 band A2-3.1 by fluorescence in situ hybridization.

Alternative Splicing↗
PubMed1998

Human keratin-1.bcl-2 transgenic mice aberrantly express keratin 6, exhibit reduced sensitivity to keratinocyte cell death induction, and are susceptible to skin tumor formation.

Nonmelanoma skin cancers (NMSC) are among the most common malignancies in the world. Typically, these neoplasms grow slowly and are comparatively indolent in their clinical behavior. The most frequent molecular alterations implicated in the pathogenesis of these neoplasms involve genes known to be regulators of cell death including p53, Ha-ras and bcl-2. In order to evaluate the significance cell death deregulation during skin carcinogenesis, we generated a transgenic mouse model (HK1.bcl-2) using the human keratin 1 promoter to target the expression of a human bcl-2 minigene to the epidermis. Transgenic HK1.bcl-2 protein was expressed at high levels specifically in the epidermis extending from the stratum basale through the stratum granulosum. The epidermis of HK1.bcl-2 mice exhibited multifocal hyperplasia without associated hyperkeratosis and aberrant expression of keratin 6. The rate of proliferation was similar in HK1.bcl-2 and control epidermis although suprabasal BrdUrd incorporating cells were present only in HK1.bcl-2 skin. Keratinocytes from the HK1.bcl-2 mice were significantly more resistant to cell death induction by U.V.-B, DMBA, and TPA, compared to control keratinocytes. Furthermore, papillomas developed at a significantly greater frequency and shorter latency in the HK1.bcl-2 mice compared to control littermates following initiation with DMBA and promotion with TPA. Together these results support a role for bcl-2 in the pathogenesis of NMSC.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Retinoic acid regulates gonadotropin-releasing hormone (GnRH) release and gene expression in the rat hypothalamic fragments and GT1-1 neuronal cells in vitro.

The present study attempts to examine the possible involvement of retinoic acid (RA) in the regulation of gonadotropin-releasing hormone (GnRH) release and gene expression in the rat hypothalamic fragments and GT1-1 neuronal cells in vitro. During a short-term period (2h), RA (0.01-1 microM) increased GnRH release in a dose-related manner. Time-course experiments showed that RA rapidly increased GnRH release by 30 min in both cells. RA-induced GnRH release was slowly attenuated in the next incubation period in hypothalamic fragments, but rapidly returned to control levels in GT-1 cells. In hypothalamic fragments, GnRH mRNA levels decreased, but in GT1-1 cells, no change in GnRH mRNA levels was observed. We then extended the incubation time to see any changes in GnRH mRNA levels by RA in GT1-1 cells. In a long term (up to 48 h), RA increased GnRH mRNA levels in a dose- and time-related manner. Significant increase in GnRH mRNA levels by RA (at higher than 10 nM) was observed within 12h. Transient transfection experiments with a luciferase reporter vector containing more than 3 kb of the rat GnRH 5'-flanking region (-3002 to +88) revealed that RA also increased the rat GnRH promoter activity in a similar dose-and time-dependent manner, suggesting that increases in GnRH mRNA levels are attributable, at least in part, to the enhanced gene transcription. The promoter analysis with the 5'-deletional constructs demonstrated that cis-elements responsible for the RA action may reside within -1640/-1438 of the rat GnRH promoter, where multiple direct or palindromic arrangements of the AGGTCA-related sequences exist. We also showed that GT1-1 cells as well as the hypothalamic tissues express mRNA for multiple subtypes of retinoid receptors, and that reporter plasmids with three copies of the strong retinoic acid response element (RARE) were activated by 80 folds upon treatment with RA in GT1-1 cells, suggesting that retinoid receptors in GT1-1 cells are functional. Taken together, the present study strongly suggests that RA is an important regulator of the GnRH neurons.

Animals↗
PubMed1998

Effect of controlled hypotension combined with hemodilution on gastric intramural pH.

STUDY OBJECTIVE: To evaluate the effect of controlled hypotension combined with hemodilution on gastric intramural pH in the clinical setting. DESIGN: Randomized, prospective study. SETTING: Inpatient surgery at Nagasaki Rosai Hospital. PATIENTS: 30 ASA physical status I and II patients scheduled for total hip arthroplasty. INTERVENTIONS: Patients were randomly divided into two groups. Group A (n = 15) received controlled hypotension with mild hemodilution. Group B (n = 15) received controlled hypotension with moderate hemodilution. Hemodilution was carried out after induction of anesthesia. Drawn blood was replaced with 6% hydroxyethyl starch solution. Final hematocrit values were 32 +/- 2% (mean +/- SD) in Group A and 23 +/- 2% in Group B. Controlled hypotension was induced with prostaglandin E1 (PGE1) to maintain mean arterial blood pressure at 55 mmHg for 80 minutes. MEASUREMENTS AND MAIN RESULTS: Measurements included gastric intramural pH (pHi), arterial blood pH (pHa), and plasma lactate. These indices were measured before hemodilution, after hemodilution, 80 minutes after starting hypotension, 60 minutes after recovery from hypotension, and on the first postoperative day. The value of pHi was measured by tonometry. The pHa and lactate values showed no change in either Group A or Group B throughout the time course. Gastric pHi values showed no change in Group A throughout the time course. The pHi value in Group B showed a significant decrease from 7.420 +/- 0.028 to 7.339 +/- 0.034 (p < 0.05) after hemodilution, while it showed no further decrease at 80 minutes after starting hypotension (7.331 +/- 0.039) and 60 minutes after recovery from hypotension (7.330 +/- 0.048). CONCLUSION: The results suggest that moderate hemodilution, such as 23% of hematocrit value, might impair oxygenation in gastrointestinal mucosa, whereas controlled hypotension induced by PGE1 combined with the hemodilution would not increase this impairment.

Aged↗
PubMed1998

Molecular interaction of CD1b with lipoglycan antigens.

The ability of human CD1b molecules to present nonpeptide antigens is suggested by the T cell recognition of microbial lipids and lipoglycans in the presence of CD1b-expressing antigen-presenting cells. We demonstrate the high-affinity interaction of CD1b molecules with the acyl side chains of known T cell antigens, lipoarabinomannan, phosphatidylinositol mannoside, and glucose monomycolate. Furthermore, CD1b-antigen binding was optimal at acidic pH, consistent with the known requirement for endosomal acidification in CD1b-restricted antigen presentation. The mechanism for CD1b-ligand interaction involves the partial unfolding of the alpha helices of CD1b at acidic pH, revealing a hydrophobic binding site that could accommodate lipid. These data provide direct evidence that the CD1b molecule has evolved unique biochemical properties that enable the binding of lipid-containing antigens from intracellular pathogens.

Anilino Naphthalenesulfonates↗