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Biomedical subjects

S W Yang

Publications and source records attributed to S W Yang.

At least 19 recordsLinked to original sources
PubMed2006

In vitro skin penetration and pharmacodynamic evaluation of prostaglandin E1 ethyl ester, a vasoactive prodrug of prostaglandin E1, formulated into alcoholic hydrogels.

Alcoholic hydrogels containing prostaglandin E1 ethyl ester (PGE1-EE), a prodrug of PGE1 as a therapeutic agent for erectile dysfunction, were formulated. The prodrug was stable against chemical hydrolysis in aqueous solution (pH 7.4), devoid of esterase activities, but was hydrolyzed to the parent drug in rat skin homogenates within 240 min. In the rat skin penetration study for 24 h, the steady-state flux values (microg/cm2/h) of PGE1-EE and PGE, from alcoholic hydrogels having 20% ethanol content were 7.6 and 1.8, respectively. PGE1-EE was superior to PGE, from a skin penetration point of view due to its increased lipophilicity. The fastest skin penetration rate was obtained for PGE1-EE in 20% alcoholic hydrogel together with limonene or cineole. These formulations increased the flux of PGE1-EE up to about 4-fold compared to control hydrogel in the absence of penetration enhancers. In the pharmacodynamic study using a cat, alcoholic hydrogel with limonene or cineole showed a significant effect in terms of increasing intracavernosal pressure compared to control hydrogel. Therefore, the transdermal alcoholic hydrogel formulation of PGE1-EE with limonene or cineole can be a promising transdermal delivery system to overcome inconvenience associated with frequent intracavernosal injections for the treatment of erectile dysfunction.

Alcohols↗
PubMed2005

Clinical implications of N epsilon-(carboxymethyl)lysine, advanced glycation end product, in children and adolescents with type 1 diabetes.

AIM: The aim of this study was to investigate the relationship between serum levels of the glycoxylation product N(epsilon)-(carboxymethyl)lysine (CML) and development of chronic diabetic complications and degree of diabetic control in children and adolescents with type 1 diabetes. METHODS: The serum levels of CML were measured in 87 patients with uncomplicated type 1 diabetes mellitus (12.7 +/- 4.6 years of age) and in seven patients with background retinopathy, microalbuminuria or neuropathy (18.2 +/- 5.2 years of age) and compared with those in 64 normal control subjects (12.6 +/- 5.2 years of age). The mean durations of diabetes in uncomplicated and complicated patients were 5.0 +/- 3.4 years (0.1-14 years), and 8.6 +/- 5.0 years (3.1-18 years), respectively. The serum levels of CML were measured by enzyme-linked immunosorbent assay using a monoclonal anti-CML antibody (6D12). RESULTS: The serum levels of CML were significantly higher in the patient group than those in the control group; 0.85 +/- 0.37 (0.37-1.93) U/ml vs. 0.56 +/- 0.23 (0.15-1.05) U/ml (p < 0.001) and significantly higher in the patient group with chronic complications than those in patient group without chronic complications; 1.06 +/- 0.39 (0.72-1.78) U/ml vs. 0.83 +/- 0.36 (0.37-1.93) U/ml (p < 0.05). Weak, but statistically significant relationship between CML levels and haemoglobin A(1c) levels at the measurement of CML was observed (r = 0.29, p < 0.05). CONCLUSIONS: Our data are suggesting that higher serum levels of CML are involved in the development of chronic diabetic complications, and serum levels of CML reflect the degree of diabetic control for a long duration in type 1 diabetic children and adolescents.

Adolescent↗
PubMed2003

Effects of environmental endocrine disruptors on the sex differentiation in Korean rockfish, Sebastes schlegeli.

The effects of estradiol-17beta, methyltestosterone, tributyltin, bisphenol A and 2,4-dinitrophenol on sex differentiation were investigated in the Korean rockfish, Sebastes schlegeli. The 51 day-old fry with undifferentiated gonads were fed with food containing the chemicals at 0.05, 0.5, 5, 50 and 100 micro/g diet for 29 days. Sex ratio and gonadal abnormality after the chemical treatment were determined by histological examination of gonads. In control group, the sex ratio of fry was 1:1.3 (female:male), and more males than females appeared. The sex of fry fed with estradiol-17beta at 5, 50 and 100 micro/g diet was all females. Feminization of the fry was induced by exogenic estradiol-17beta. In the methyltestosterone group, sex ratio of fry was 1:10.2 in 0.05 micro/g diet, 1:2.4 in 0.5 micro/g diet, 1:3.1 in 5 micro/g diet, 1:1.2 in 50 micro/g diet and 1:2.3 in 100 micro/g diet. Masculinization of the fry was induced by methyltestosterone at the lowest concentration. Furthermore, intersex of the fry was observed. The number of intersex fry was 23.3, 25.0 and 35.3 at 0.5, 5 and 50 micro/g diet of methyltestosterone, respectively. Sex ratio of bisphenol A group showed no difference with that of the control. The sex of fry fed with 2,4-dinitrophenol at 5, 50 and 100 micro/g diet was all females. 2,4-dinitrophenol should be considered as a new member of endocrine disruptors. In tributyltin group, the sex ratio of fry at 100 micro/g diet of tributyltin was 5.4:1. Tributyltin induced the feminization of the fry at the highest dose. Tributyltin showed an estrogenic effect in the Korean rockfish in contrast to an androgenic effect in gastropods.

Administration, Oral↗
PubMed2001

Three new phenolic compounds from a manipulated plant cell culture, Mirabilis jalapa.

Bioassay-guided fractionation of an organic extract of the cell mass from a manipulated plant cell culture of Mirabilis jalapa led to the isolation and subsequent identification of three new phenolic compounds, 1, 2, and 3. The isoflavone 1 and dehydrorotenoid 2 were identified as the principal antifungal principles from this plant cell culture with IC(50)'s of 25 and 48 microg/mL, respectively, against the test organism, Candida albicans DSY1024. The rotenoid 3 was inactive at 200 microg/mL in this assay.

Antifungal Agents↗
PubMed2001

Refractive changes of congenital entropion and epiblepharon on surgical correction.

In order to investigate the refractive error, amblyopic frequency, and refractive change, if any, following recovery of cornea injury through surgery of epiblepharon and congenital entropion patients, we retrospectively reviewed the sex distribution, age at operation, chief complaints, preoperative and postoperative refractive errors, and best corrected visual acuity in 160 previously operated patients. The average age at operation was 7.9 years. The preoperative best corrected visual acuity of 133 eyes (41.6%) was below 5/9. Ninety-five eyes (29.7%) were preoperative myopes above -1.0D; 77 eyes (24%) were hyperopes above +1.0D; and 163 eyes were astigmatic above -1.0D. Of 228 eyes that were followed up for more than one year, 66 eyes demonstrated a best corrected visual acuity of below 5/9. There was no significant difference in the change in corneal astigmatism following surgery between the group under the age of 7 and the group over the age of 7. However, the mean best corrected visual acuity at postoperative one year was 6/9, which was significantly different from the preoperative value (P=0.006). Concurrent postoperative glasses correction and amblyopic therapy is indicated because the incidence of refractive errors and amblyopia is higher in epiblepharon and congenital entropion.

Adolescent↗
PubMed2001

Mucinous cystadenoma coexisting with stromal tumor with minor sex-cord elements of the ovary: a case report.

Mucinous neoplasms occur rarely in association with cystic teratoma, Sertoli-Leydig cell tumor, granulosa cell tumor or carcinoid tumor. Several cases of an ovarian stromal tumor with minor sex-cord elements have been reported in the literatures. However, there has been no report about an ovarian mucinous neoplasm coexisting with a stromal tumor with sex-cord elements yet. We report a case of an ovarian neoplasm composed of both mucinous cystadenoma and stromal tumor with minor sex-cord elements in a 58-yr-old female. The ovary including the mass measured 5 cm in size. On section, it revealed an unilocular cyst (4.5 cm in diameter) filled with mucinous fluid. There was a round, yellow, solid nodule, 1.5 cm in diameter within the wall. Microscopically, the cyst was lined by a single layer of endocervical mucinous epithelium and the nodule was composed of spindle cells showing an intersecting and whorled arrangement. There were cell nests showing polygonal shape with abundant cytoplasm among the spindle cells. They showed immunoreactivity for inhibin and did not have any connection with the adjacent mucinous epithelium. Therefore, we interpret the mucinous cystadenoma as having arisen de novo.

Cystadenoma, Mucinous↗
PubMed2001

Spinal deformities in Noonan syndrome: a clinical review of sixty cases.

BACKGROUND: Skeletal abnormalities, including spinal deformities, in Noonan syndrome have been described, but no detailed and systematic study of such spinal deformities has been presented in the literature. METHODS: The cases of sixty patients with Noonan syndrome were reviewed retrospectively, and the general appearance, growth disturbance, and mental status of the patients were documented. Spinal deformities were evaluated radiographically, and the frequency, pattern, and severity of the curves were documented. RESULTS: Spinal deformity was present in eighteen (30%) of the sixty patients. Two patients had congenital spinal deformity. Of the remaining sixteen patients with scoliosis, nine had a single thoracic curve, four had a single thoracolumbar curve, and three had a double major curve. Thoracic lordosis was also present in three of these sixteen patients. No patient had only increased kyphosis or lordosis. The mean age when the spinal deformities were detected was nine years; seven deformities were detected before the age of seven years. Overall, surgery was recommended to eleven of the eighteen patients; it was recommended for the treatment of scoliosis (mean, 68.5 degrees; range, 45 degrees to 125 degrees ) in eight patients and for the treatment of an associated thoracic lordosis (8 degrees, 15 degrees, and 18 degrees ) in three. Seven of the eleven patients underwent spinal arthrodesis. The operation was deferred in one patient because malignant hyperthermia developed during the induction of anesthesia. CONCLUSIONS: Scoliosis with an associated thoracic lordosis occurs more frequently in Noonan syndrome than has been reported previously. Since the deformities tend to develop early and are relatively severe, a clinical and, if necessary, radiographic assessment of the spine with careful follow-up should be performed for early detection and treatment of spinal deformity. Although malignant hyperthermia is rare, all patients with Noonan syndrome should be considered to be at risk for the development of this complication before operative treatment.

Adolescent↗
PubMed2000

Analysis of essential leucine residue for catalytic activity of novel thermostable chitosanase by site-directed mutagenesis.

Bacterial chitosanases share weak amino acid sequence similarities at certain regions of each enzyme. These regions have been assumed to be important for catalytic activities of the enzyme. To verify this assumption, the functional importance of the conserved region in a novel thermostable chitosanase (TCH-2) from Bacillus coagulans CK108 was investigated. Each of the conserved amino acid residues (Leu64, Glu80, Glu94, Asp98, and Gly108) was changed to aspartate and glutamine or asparagine and glutamate by site-directed mutagenesis, respectively. Kinetic parameters for colloidal chitosan hydrolysis were determined with wild-type and 10 mutant chitosanases. The Leu64 --> Arg and Leu64 --> Gln mutations were essentially inactive and kinetic parameters such as Vmax and kcat were approximately 1/10(7) of those of the wild-type enzyme. The Asp98 --> Asn mutation did not affect the Km value significantly, but decreased kcat to 15% of that of wild-type chitosanase. On the other hand, the Asp98 --> Glu mutation affected neither Km nor kcat. The observation that approximately 15% of activity remained after the substitution of Asp98 by Asn indicated that the carboxyl side chain of Asp98 is not absolutely required for catalytic activity. These results indicate that the Leu64 residue is directly involved in the catalytic activity of TCH-2.

Amino Acid Sequence↗
PubMed2000

Relationship of insulin-like growth factor-I, insulin-like growth factor binding protein-3, insulin, growth hormone in cord blood and maternal factors with birth height and birthweight.

BACKGROUND: To determine whether the following factors are related to birthweight or birth height, we measured insulin-like growth factor (IGF)-I, insulin-like growth factor binding protein (IGFBP)-3, insulin and growth hormone (GH) levels in cord blood and also observed the relationship between birthweight, birth height and maternal factors. METHODS: One hundred and ninety-four cord bloods were collected, 106 from males and 88 from females. Three newborns were small for gestational age (SGA), 168 were appropriate (AGA) and 23 were large (LGA); 21 newborns were preterm and 172 were term. RESULTS: Levels of IGF-I and IGFBP-3, measured by enzyme-linked immunosorbent assay, were significantly lower in preterm babies (35.3 +/- 15.1 and 1025.6 +/- 562.8 ng/mL, respectively) than in term babies (61.6 +/- 39.5 and 1252.6 +/- 403.2 ng/mL, respectively; P < 0.01), but neither insulin nor GH levels, measured by radioimmunoassay, showed any significant difference between the two groups (P > 0.05). Among term babies, IGF-I and IGFBP-3 levels were significantly higher in the LGA group (96.1 +/- 34.1 and 1544.7 +/- 418.1 ng/mL, respectively) than in the AGA group (56.4 +/- 37.6 and 1212.8 +/- 383.4 ng/mL, respectively; P < 0.01). Levels of IGF-I and IGFBP-3 showed significant correlation with birthweight and length, respectively (P < 0.01), although GH and insulin levels did not (P > 0.05). There was a significant correlation between IGF-I and IGFBP-3 levels (P < 0.01, r = 0.64), but IGF-I and IGFBP-3 levels showed no relationship with GH or insulin levels. Birthweight correlated significantly with prepartum maternal weight, maternal weight gain and maternal height (P < 0.05), but birth length correlated significantly only with maternal height (P < 0.05). CONCLUSIONS: Our results suggest that fetal growth depends on fetal levels of IGF-I and IGFBP-3 and maternal factors, not on insulin or GH. Levels of IGF-I and IGFBP-3 may not be regulated by insulin alone, but by the complex interactions between several factors, such as insulin, GH and maternal factors.

Birth Weight↗
PubMed2000

Bcl-2 expression in sputum eosinophils in patients with acute asthma.

BACKGROUND: Eosinophils play a pivotal role in asthmatic airway inflammation. Apoptosis is thought to be critically relevant in promoting the clearance of inflammatory cells and the resolution of inflammation. Bcl-2 inhibits apoptosis in cellular systems. A study was undertaken to determine whether bcl-2 expression in sputum reflects the clinical severity of patients with asthma. The relationship between bcl-2 expression in sputum eosinophils and eosinophil activation markers such as interleukin (IL)-5 and eosinophil cationic protein (ECP) levels in sputum supernatant was evaluated. METHODS: Sputum was obtained from 18 patients with asthma. Fresh expectorated sputum separated from saliva was treated with an equal volume of dithiothreitol 0.1%, cytospun for cell differentials and bcl-2 stain, and the supernatant was collected for biochemical assay. Bcl-2+ eosinophils were stained using immunocytochemistry, ECP was measured by fluoroimmunoassay, and IL-5 was detected by sandwich enzyme linked immunosorbant assay. RESULTS: Twelve patients with severe or life threatening asthma had more bcl-2+ eosinophils (mean difference 46.8% (95% CI 27.0 to 66.6), p<0.01) and a higher ECP level (p<0.01) in the sputum than those with mild to moderate asthma (n = 6). IL-5 was frequently detected in patients with severe or life threatening asthma (11/12 versus 1/6, p<0.01). There was a significant positive correlation between bcl-2+ eosinophils and ECP levels (r = 0.61, p<0.01) and between bcl-2+ eosinophils and IL-5 levels (r = 0.83, p<0.01). There was a significant negative correlation between bcl-2+ eosinophils and FEV(1)/FVC (r = -0.54, p<0.05). CONCLUSION: The increased expression of bcl-2 in eosinophils from sputum of subjects with severe asthma suggests that bcl-2 may prolong survival and decrease apoptosis of airway eosinophils in asthma.

Acute Disease↗
PubMed2000

The relationship of the levels of leptin, insulin-like growth factor-I and insulin in cord blood with birth size, ponderal index, and gender difference.

In humans, serum levels of leptin correlate with total body fat in both adults and children. After collecting cord blood from 156 term neonates (82 males, 74 females; 132 AGA and 22 LGA), we measured the cord levels of leptin, insulin and IGF-I to determine the relationships between these three hormones and relationships of these hormones with birth size (birth weight and ponderal index for adiposity in newborn) and gender. The leptin and IGF-I levels were significantly higher in the LGA group (9.2+/-4.0 ng/ml and 96.1+/-34.1 ng/ml, respectively) than in the AGA group (4.8+/-3.8 ng/ml and 56.4+/-37.6 ng/ml, respectively). A significant positive correlation was observed between leptin levels and birth weight, and a weaker correlation between leptin levels and birth height. IGF-I level significantly correlated with birth weight and birth height, but there was no correlation between the levels of insulin and birth weight. There was no relationship between the levels of IGF-I, insulin and leptin. Ponderal index was higher in LGA than in AGA. A significant correlation was also observed between the levels of leptin and ponderal index, but not between the levels of insulin or IGF-I and ponderal index. The levels of leptin and ponderal index were higher in females than males despite no gender differences in gestational age and birth weight. In conclusion, our results suggest that the level of IGF-I is a useful index for fetal growth during late gestation, and the development of adipose tissue is the major determinant of fetal serum leptin levels, the production of which is not regulated by insulin or IGF-I. In addition, a gender difference with a higher level of leptin in female neonates suggests that sexual dimorphism in adipose tissue already exists in utero.

Birth Weight↗
PubMed2000

Two cases of orbital infarction syndrome.

Orbital infarction syndrome is defined as ischemia of all intraorbital and intraocular structures. It is a rare disease caused by rich anastomotic vascularization of the orbit. It can occur secondary to different conditions, such as, acute perfusion failure, systemic vasculitis, orbital cellulitis and vasculitis. It results in orbital and ocular pain, total ophthalmoplegia, anterior and posterior segment ischemia, and acute blindness. We report here upon two cases of orbital infarction with similar presentations but with different causes, namely, mucormycosis and as a postoperative complication of intracranial aneurysm, discuss the possible mechanisms of orbital infarction, and present a review of the literature on the topic. The prompt recognition of clinical pictures and rapid diagnosis is essential for the early treatment of orbital infarction, since its progression is very rapid and it can be even fatal.

Adult↗
PubMed2000

Lingual osteoma: case report.

Lingual osteoma, a rare clinical entity, has been found mainly in the posterior region of tongue. It mostly affects women in their third and fourth decades of life and occurs less frequently in men. We report an unusual case of a 42-year-old male patient who developed a lingual osteoma near the foramen cecum. The patient underwent excision of the tumor mass under local anesthesia and had an uneventful postoperative course. Symptoms of the mass effect were noted to resolve after surgical intervention. Histologically, mature lamellar bone with haversian systems was seen. The pathogenesis of this rare tumor is a controversial problem and its nomenclature also remains an issue of debate. Discussion of the controversial pathogenesis of lingual osteoma and a review of the literature on its clinical characteristics are included in this report.

Adult↗
PubMed1999

A simple method of predicting hormonal outcome in children with intracranial germinoma.

Even a small intracranial germinoma (GE) frequently provokes pituitary hypofunction. We evaluated the relationships between preoperative hormonal status and hormonal outcome and between size of suprasellar mass and hormonal outcome in 22 children with intracranial pure GE to determine whether or not these can reflect the degree of hypothalamo-pituitary axis destruction. Preoperative hormonal status was graded from I to IV according to the serum prolactin level (s-PRL) and thyroid function (TF). The hormonal outcome was estimated by the type and the number of hormonal replacement medications taken on the basis of the triple load test and endocrinological examinations at the time of the last follow-up (median period: 43 months). Fifteen of the 22 patients had suprasellar lesions. All 13 patients who had diabetes insipidus (DI) at presentation needed desmopressin acetate (DDAVP) during the follow-up period. The correlation between increment of preoperative grade and the increment in the number of hormones to be replaced was statistically significant (P<0.05). This preoperative grading was a more reliable predictor than the size of suprasellar tumor. In conclusion, preoperative grading by s-PRL and TF test is useful for the prediction of posttreatment hormonal replacement in children with intracranial pure GE.

Adolescent↗
PubMed1999

The effect of morphine on responses of nucleus ventroposterolateralis neurons to colorectal distension in the rat.

In 71 halothane-anesthetized rats, we characterized the responses of single neurons in the nucleus ventroposterolateralis (VPL) of the thalamus to a noxious visceral stimulus (colorectal balloon distension; CRD) and studied the effects of intravenous morphine on these responses using standard extracellular microelectrode recording techniques. One hundred nine neurons were isolated on the basis of spontaneous activity. Sixty-four (59%) responded to CRD, of which 52 (81 %) had excitatory and 12 (19%) had inhibitory responses. Neurons showed graded responses to graded CRD pressures (20-100 mmHg), with maximum excitation or inhibition occurring at 80 mmHg. Responses to noxious (pinch, heat) and innocuous (brush, tap) cutaneous stimuli were studied in 95 of the VPL neurons isolated. Eighty-three of these neurons (48 CRD responsive and 35 CRD nonresponsive) (87%) had cutaneous receptive fields, of which 96% were small and contralateral and 4% were large and contralateral or bilateral. Ninety-four percent of these neurons responded to both noxious and innocuous cutaneous stimulation, and 6% responded to only noxious stimulation. No neurons responded solely to innocuous stimulation. Cumulative doses of morphine (0.125, 0.25, 0.5, 1, and 2 mg/kg, i.v) produced statistically significant dose-dependent attenuation of neuronal responses to CRD. Naloxone (0.4 mg/ kg, i.v.) reversed the effects of morphine. Morphine and naloxone had no significant effects on spontaneous activity. These data support the involvement of VPL neurons in visceral nociception and are consistent with a role of VPL in sensory-discriminative aspects of nociception.

Analgesics, Opioid↗
PubMed1999

Synthesis and biological evaluation of analogues of cryptolepine, an alkaloid isolated from the Suriname rainforest.

Bioassay-guided fractionation of an extract of a mixture of Microphilis guyanensis and Genipa americanacollected in the rainforest of Suriname yielded the known alkaloid cryptolepine (2) as the major active compound in a yeast bioassay for potential DNA-damaging agents; the same compound was later reisolated from M. guyanensis. The structure of cryptolepine was identified unambiguously by spectral data and by its total synthesis. Several cryptolepine derivatives (3-29, 32-41) were synthesized based on modifications of the C-2, N-5, N-10, and C-11 positions. Two cryptolepine dimers (30, 31) were also prepared. The structure modifications did not result in compounds with a higher potency than the parent compound cryptolepine in the yeast assay system, although some derivatives did show significant activity. Selected compounds (6, 7, 17, 22, 23, 26, and 27) were also tested for cytotoxicity in mammalian cell culture, and two compounds showed significant cytotoxic activity.

Alkaloids↗
PubMed1999

O- and N-methylation in the biosynthesis of staurosporine.

The feeding of (13)C- and (2)H-enriched methionine to Streptomyces staurosporeus established that the methyl carbon and proton source of both the 3'-O- and 4'-N-methyl groups of staurosporine (1) was methionine and that all three methyl protons from methionine were retained on 1. In the presence of the methyltransferase inhibitor, sinefungin, the biosynthesis of staurosporine was blocked at the last step, O-methylation. An intermediate, 3'-demethoxy-3'-hydroxystaurosporine (2), was efficiently accumulated in the medium. Other general methyltransferase inhibitors failed to produce any other staurosporine intermediates or analogues.

Chromatography, High Pressure Liquid↗