Biomedical subjects

S Y Han

Publications and source records attributed to S Y Han.

At least 73 records · Page 4Linked to original sources

PubMed2000

Nonocclusive mesenteric ischemia in a patient on maintenance hemodialysis.

UNLABELLED: Nonocclusive mesenteric ischemia (NOMI) is known to occupy about 25% to 60% of intestinal infarction. NOMI has been reported to be responsible for 9% of the deaths in the dialysis population and the postulated causes of NOMI include intradialytic hypotension, atherosclerosis and medications, such as diuretics, digitalis and vasopressors. Clinical manifestations, such as fever, diarrhea and leukocytosis, are nonspecific, which makes early diagnosis of NOMI very difficult. CASE: A 66-year-old woman on maintenance hemodialysis for 5 years was admitted with syncope, abdominal pain and chilly sensation. Since 7 days prior to admission, blood pressure on the supine position during hemodialysis had frequently fallen to 80/50 mmHg. Four days later, she complained of progressive abdominal pain. Rebound tenderness and leukocytosis (WBC 13900/mm3) with left shift were noted. Stool examination was positive for occult blood. Abdominal CT scan showed a distended gall bladder with sludge. Under the impression of acalculous cholecystitis, she was operated on. Surgical and pathologic findings of colon colon were compatible with NOMI. Because of recurrent intradialytic hypotension, we started midodrine 2.5 mg just before hemodialysis and increased the dose up to 7.5 mg. After midodrine therapy, blood pressure during dialysis became stable and the symptoms associated with hypotension did not recur. CONCLUSION: As NOMI may occur within several hours or days after an intradialytic hypotensive episode, abdominal pain should be carefully observed and NOMI should be considered as a differential diagnosis. In addition, we suggest that midodrine be considered to prevent intradialytic hypotensive episodes.

Aged↗

PubMed2000

Expression of nm23 protein in human osteosarcoma in relationship with early metastasis.

Nm23 protein expression was analyzed by immunohistochemical staining using formalin-fixed, paraffin-embedded sections from 39 cases with osteosarcomas and compared with the histologic findings and early metastasis for the purpose of detecting nm23 expression in osteosarcoma and elucidating the clinical significance of its expression. Immunoreactivity of nm23 protein was detected in 48.7% of the total cases. There was no statistical difference between nm23 expression and early metastasis, but there was a trend for cases with nm23 expression to progress to early metastasis within 1 year after operation. The role of nm23 as a tumor metastasis suppressor in osteosarcomas appeared less prominent.

Adolescent↗

PubMed2000

Functional evaluation of p53 and PTEN gene mutations in gliomas.

We screened mutations of two major tumor suppressor genes, p53 and PTEN, in 66 human brain tumors using a yeast-based functional assay and cDNA-based direct sequencing, respectively. The frequency of p53 mutations was 28.8% (19 of 66) and was higher in anaplastic astrocytoma (9 of 14, 64.3%,) than in glioblastoma multiforme (GBM; 7 of 27, 25.9%,), supporting previous speculation that there are at least two genetic pathways leading to GBM, a de novo pathway without p53 mutation and a "progressive" pathway with p53 mutation. PTEN mutation was observed in 8 of 64 tumors (12.5%), mainly GBMs (7 of 26, 26.9%), both with and without p53 mutation. These results suggest that mutation of the PTEN gene is a later event than that of the p53 gene in glioma progression and is associated with both the genetic pathways. All of the detected PTEN missense mutations and an in-frame small deletion inactivated PTEN phosphoinositide phosphatase activity in vitro. Because the tumors containing PTEN mutations also showed loss of heterozygosity in the chromosome 10q23 region flanking the PTEN gene, our data clearly indicate that inactivation of both PTEN alleles occurs in a subset of high-grade gliomas, therefore confirming the previous idea that PTEN acts as a tumor suppressor gene.

Adolescent↗

PubMed2000

[The somatic embryogenesis and establishment of transformation experiment system in Larix principis-Rupprechtii].

Larix principis-Rupprechtii is one of the superior afforestation forest trees growing in north China. Embryogenic cultures were initiated from immature zygotic embryos of Larix principis-Rupprechtii on S culture medium containing 2, 4-D 0-2.2 mg/L, KT and BA each at 0-0. 8 mg/L. Embryogenic calli were subcultured and multiplicated on S + B culture medium containing dropping off each hormone concentration. We set up 33 steady-going embryogenic cell lines; We studied on the growth stage and genotype differences of every embryogenic cell lines; and Finded more than 10 high-frequency somatic embryogenesis cell lines such as 2K, 2T, 2I, 2J, 3C etc.. The number of 2T somatic embryos reaches 314/per gram of embryogenic tissue and the number of 3C somatic embryos is 185/per gram of embryogenic tissue. The re-induction method of Larix principis-Rupprechtii from somatic embryos was used to produce renewable embryogenic cultures and steady-going embryogenic cell lines effectively. Mature somatic embryos can germinate and develop further into plantlets when they are isolated and cultured on a hormone-free WPM culture medium. The regeneration plantlets were obtained. Furthermore, the transformation with a truncated gene of Bacillus thuringensis (B. t) were carried out, the PCR showed positive results, because of this, embryogenic cell line of Larix principis-Rupprechtii can be used for transformation experiments to support further breeding in forestry.

Cell Line↗

PubMed1999

Alterations of the DR5/TRAIL receptor 2 gene in non-small cell lung cancers.

Chromosome 8p21-22 is a frequent site of allelic deletions in many types of human tumors, including non-small cell lung cancer (NSCLC). Tumor necrosis factor-related apoptosis-inducing ligand-receptor 2 (TRAIL-R2) is a cell-surface receptor involved in cell death signaling. The TRAIL-R2 gene recently has been mapped to chromosome 8p21-22. To explore the possibility that the TRAIL-R2 gene might be the relevant gene to the frequent deletion of 8p21-22 in NSCLC, we have analyzed the entire coding region and all splice sites of TRAIL-R2 for the detection of the somatic mutations in a series of 104 NSCLCs. Overall, 11 tumors (10.6%) were found to have TRAIL-R2 gene mutations in the death domain known to be involved in the transduction of an apoptotic signal. Our data indicate that somatic mutation of TRAIL-R2 may play a role in the pathogenesis of some NSCLCs and that the TRAIL-R2 gene is one of the genes relevant to the frequent loss of chromosome 8p21-22 in NSCLC.

Adenocarcinoma↗

PubMed1999

Determination of melatonin in biological samples by capillary electrophoresis.

The determination of melatonin (MLT) in physiological samples was investigated using capillary electrophoresis (CE). Mouse blood was collected in tubes containing EDTA, centrifuged at 1500 g for 20 min at 4 degrees C, and stored at -20 degrees C. Plasma samples were extracted with dichloroethane, centrifuged and the aqueous phase was discarded. Then the organic phase was evaporated to dryness. The residue was dissolved in deionized water and filtered with a microfilter (0.22 micron). Separations were carried out using a CE system equipped with a fused silica capillary [80 cm (effective length 52 cm) x 75 microns I.D.] and an ultraviolet-visible detector (200 nm), and programmed to provide 25 mM 2-(N-morpholino)ethanesulfonic acid (pH 5.7). Injection was performed hydrostatically by elevating the sample by 10 cm at the cathodic side of the capillary. The calibration curve, reproducibility, recovery and limit of detection were examined, and validation of the method was performed. The result showed that MLT in blood could be easily determined with the new method.

Animals↗

PubMed1999

Clonazepam release from bioerodible hydrogels based on semi-interpenetrating polymer networks composed of poly(epsilon-caprolactone) and poly(ethylene glycol) macromer.

Poly(ethylene glycol)(PEG) macromers terminated with acrylate groups and semi-interpenetrating polymer networks (SIPNs) composed of poly(epsilon-caprolactone)(PCL) and PEG macromer were synthesized to obtain a bioerodible hydrogel. Polymerization of PEG macromer resulted in the formation of cross-linked gels due to the multifunctionality of macromer. Glass transition temperature (Tg) and melting temperature (Tm) of PEG networks and PCL in the SIPNs were inner-shifted, indicating an interpenetration of PCL and PEG chains. Water content in the SIPNs increased with increasing PEG weight fraction due to the hydrophilicity of PEG. The amount of clonazepam (CNZ) released from the SIPNs increased with higher content in the SIPNs, lower drug loading, lower concentration of PEG macromer during the SIPNs preparation, and higher molecular weight of PEG. In particular, a combination with low PEG content and low CNZ solubility in water led to long-term constant release from these matrices in vitro and in vivo.

Animals↗

PubMed1999

Monoacetyldiglycerides as new Ca2+ mobilizing agents in rat pancreatic acinar cells.

Several monoacetyldiglycerides were synthesized from glycerol in search for new Ca2+ mobilizing agent in vitro. All monoacetyldiglycerides except linolenoyl and phenlycyclopropylcarbonyl derivatives showed activity toward Ca2+ release in pancreatic acinar cells. Linoleoyl and docosahexaenoyl derivatives were chosen for further test and exhibited unique activity.

Acetylcholine↗

PubMed1999

Effects of chronic electroconvulsive shock on the expression of beta-adrenergic receptors in rat brain: immunological study.

The purpose of the present study is to determine the effect of chronic electroconvulsive shock (ECS) on the expression of beta-adrenergic receptors in rat brain by Western blot using mAb beta CO2, a monoclonal antibody against beta-adrenergic receptors. Rats in ECS treated groups received maximal ECS (70 mA, 0.5 second, 60 Hz) through ear-clip electrodes for 12 consecutive days. The experiment was carried out in 14 discrete regions of brain. Chronic ECS reduced the expression of beta-adrenergic receptors in frontal cortex, temporal cortex, parietooccipital cortex, hippocampus and limbic forebrain, but not in other areas of brain. The regional specificity and the magnitude of the reduction of receptor expression are well correlated with those of the reduction of receptor ligand binding, which was determined using [3H]dihydroalprenolol. To the best of our knowledge, this is the first report to demonstrate that chronic ECS decreases the expression of receptor protein in specific regions of rat brain.

Animals↗

PubMed1999

Immunohistochemical localization of FAP-1, an inhibitor of Fas-mediated apoptosis, in normal and neoplastic human tissues.

Fas, a death receptor, is widely expressed in human tissue, but its expression, although a prerequisite for the induction of apoptosis, does not predict its biological function. To understand the mechanisms of Fas resistance in human tissues in vivo, we performed immunohistochemistry using an antibody against Fas-associated phosphatase-1 (FAP-1), which interacts with the cytosolic domain of Fas and inhibits Fas-mediated apoptosis. In normal human tissues, FAP-1 immunostaining was easily detected, for example, in renal tubules, skeletal muscle, myocardiocytes, pituitary gland, parathyroid gland, pancreatic islets, hepatocytes, testicular germ cells, prostatic glands, neurons, epithelium of fallopian tube, endometrial glands, trophoblasts, bronchial epithelial cells, and some types of gastrointestinal epithelial cells. In 123 (78%) of 158 cancers of various origins, including breast carcinomas, stomach carcinomas, colon carcinomas, lung carcinomas and several types of sarcomas, variable intensities of FAP-1 expression were evident. Taken together, these findings demonstrated that FAP-1 is widely expressed in normal human tissues and partly overlapped with Fas expression described in earlier reports, suggesting that FAP-1 may have an important role in the regulation of apoptosis in vivo. In addition, FAP-1 expression in cancers suggests that many cancers may be resistant to Fas-mediated apoptosis through the action of FAP-1 in vivo.

Apoptosis↗

PubMed1999

Studies of the chemical structure of gangliosides in deer antler, Cervus nippon.

The biological activity of deer antler has been considered to originate in the gangliosides, although the structures of gangliosides have not been well elucidated. The quality of deer antler as an Asian folk medicine has often been evaluated by the amount of gangliosides contained in the crude drug. We have completed the structural determination of five gangliosides isolated from deer antler in the present study. Five ganglioside fractions were isolated and purified from deer antler, Cervus nippon, by the Folch-Suzuki partition method, DEAE-Sephadex A-25, and further by silica gel column chromatography. High field proton nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry, and fast atom bombardment-mass spectrometry studies characterized the isolated ganglioside fractions. GM3 and GD3 were present in the isolated ganglioside fractions. Samples were hydrolyzed in trifluoroacetic acid for direct compositional analysis and analyzed for sialic acid and neutral sugar without prior derivatization. Separation of the monosaccharides was achieved by HPLC on a Dionex CarboPac column eluted at a high pH. The resolved monosaccharides were identified using standard monosaccharides by pulsed amperometric detection. N-Acetyl GM3 (Neu5Ac), N-glycolyl GM3 (Neu5Gc), and N-acetyl GD3 (Neu5Ac) were present in the antler. The major ceramide moiety was composed of C16:0 or C22:0 fatty acids along with either C18 sphingosine or C20 eicosasphingosine.

Animals↗

PubMed1999

Contextualizing family risk factors for alcoholism and alcohol abuse.

OBJECTIVE: Studies of alcohol and the family should represent the full range of family types in the U.S. population. Developments from studies of family systems in other research contexts may be usefully applied to the alcohol field. METHOD: This commentary highlights important methodological and conceptual issues relevant for the design and conduct of family research. RESULTS: Data indicate major changes in the composition of the American family over the past quarter century. Some recent conceptual developments in the field of family research are relevant for studies of alcohol and the family and for intervention development. CONCLUSION: Family-based alcohol research should acknowledge and address the heterogeneity that exists among modern American families. Studies of family risk and resiliency should distinguish between threats to the family's ability to function as a whole, and threats to the well-being of individual members. Additional research is needed on the role of race and ethnicity in family processes.

Adolescent↗

PubMed1999

Hepatic involvement in hypereosinophilia: sonographic findings.

Hypereosinophilic syndrome may cause eosinophil-related tissue damage to various organs. The purpose of this paper is to describe sonographic findings in 13 patients with hypereosinophilia in whom the liver was involved. The diagnosis in these 13 patients was based on liver biopsy in seven patients with bone marrow biopsy in six patients. Eight patients had hypereosinophilic syndrome and five patients had clonorchiasis. All 13 patients had mild to marked hepatomegaly. Seven of 13 patients showed multiple round or oval hypoechoic (n = 6) or variably echogenic (n = 1) lesions measuring 1 to 2 cm with poorly defined margins in both lobes of the liver. Four patients had one or two hypoechoic lesions 3 to 4 cm in size, with geographic pattern and poorly defined margins. Two patients showed diffuse hepatomegaly with increased parenchymal echogenicity. The number of lesions and the extent of diffuse lesions seem to be proportional to the degree of eosinophilia. Hypereosinophilia may produce multiple small focal hepatic lesions or diffuse segmental or lobar echogenic lesions simulating primary or metastatic tumor of the liver.

Adult↗

PubMed1999

Isolation and characterization of monoacetyldiglycerides from bovine udder.

Monoacetyldiglycerides (MADGs) were isolated from an animal tissue, bovine udder, by solvent extraction and silica gel column chromatography. Monoacetyldiglyceride structures were identified using a variety of 1-D and 2-D NMR techniques and collision-induced dissociation (CID) tandem mass spectrometry coupled with fast atom bombardment. CID of sodium-adducted molecular ions ([M+ Na](+)) generated numerous types of product ions providing information on the double bond position of fatty acyl groups as well as fatty acid compositions. Structural analysis led to the classification of the MADGs isolated from bovine udder as 1-palmitoyl-2-lauroyl-3-acetyl-rac-glycerol, 1, 2-dimyristoyl-3-acetyl-rac-glycerol, 1-palmitoyl-2-myristoyl-3-acetyl-rac-glycerol, 1-oleoyl-2-myristoyl-3-acetyl-rac-glycerol, 1-palmitoyl-2-palmitoleoyl-3-acetyl-rac-glycerol, 1, 2-dipalmitoyl-3-acetyl-rac-glycerol, 1-linoleoyl-2-palmitoyl-3-acetyl-rac-glycerol, 1-oleoyl-2-palmitoleoyl-3-acetyl-rac-glycerol, 1-oleoyl-2-palmitoyl-3-acetyl-rac-glycerol, 1-stearoyl-2-palmitoyl-3-acetyl-rac-glycerol, 1-oleoyl-2-linoleoyl-3-acetyl-rac-glycerol, 1, 2-dioleoyl-3-acetyl-rac-glycerol, and 1-stearoyl-2-oleoyl-3-acetyl-rac-glycerol.

Animals↗

PubMed1998

Abnormal ventricular looping and abnormal laterality of the atrial chambers are the main morphogenetic mechanisms of cardiac lesions in cultured rat embryos treated with retinoic acid.

To establish the early morphogenetic mechanism in retinoid induced cardiac lesions, we investigated the morphology of the heart in cultured rat embryos treated with retinoic acid (RA) at 9.0 and 9.5 days post coitum (d.p.c). Wistar rat embryos were treated with RA (2 x 10(-7) M) for 6 hours from the embryonic day equivalent of 9.0 or 9.5 d.p.c. After further culture in an RA free medium for 2.5 days, embryos were fixed and examined with a stereomicroscope and a scanning electron microscope. Sixty three embryos were treated at 9.0 d.p.c., 14 embryos were treated at 9.5 d.p.c. and 30 embryos were used as control. Abnormal ventricular looping was seen in 31 embryos (49.2%) from the group treated at 9.0 d.p.c., and isomerism of right appendages occurred in 15 (23.8%). Embryos treated with RA at 9.5 d.p.c. showed a low incidence of abnormal ventricular looping (14.3%). We could summarize those abnormal looping as three variants of each looping. The mildest form was hypoplasia of the right ventricle observed in 20 cases. Both the right and left ventricles in the second variant were shifted far to the left or right (10 cases). The third variant was a heart with generalized hypoplasia of both ventricles (3 cases). The incidence of branchial arch anomalies was higher at 9.5 d.p.c. than at 9.0 d.p.c. (71.4% and 30.2%, respectively). Abnormalities in the ventricular looping and the atrial laterality at 9.0 d.p.c. suggest that RA induces derangement in the development of laterality, while at 9.5 d.p.c., the abnormality of the migration of neural crest cells is the principal mechanism.

Animals↗

PubMed1998

Sjögren's syndrome with acute renal failure.

We experienced a 65-year-old woman with Sjögren's syndrome who presented with acute renal failure, hypergammaglobulinemia with monoclonal gammopathy, and hypocomplementemia. She improved with steroid pulse therapy (methylprednisolone 0.5 g/day for 3 days). This patient had also sensorineural hearing loss, symmetric sensory polyneuropathy of legs, and interstitial lung disease. Ten months after recovery from acute renal failure, low-dose oral prednisolone (0.1 mg/kg/day) was withdrawn. On the third month of steroid withdrawal, acute renal failure recurred with hypergammaglobulinemia, hyperamylasemia, and autoimmune cholangitis-like biochemical derangements, which also responded to steroid pulse therapy (methylprednisolone 0.3 g/day for 3 days). When we would withdraw steroid in a patient with visceral involvement of Sjögren's syndrome, we should consider multiple clinical and laboratorial variables, including erythrocyte sedimentation rate, serum levels of IgG, total protein, C3/C4, CRP, amylase, lipase, and alkaline phosphatase. We report this case which exhibited various unusual manifestations with a review of literature.

Acute Kidney Injury↗

PubMed1995

Oxime derivatives of the intermediary oncostatic metabolites of cyclophosphamide and ifosfamide: synthesis and deuterium labeling for applications to metabolite quantification.

There is ongoing interest in the selective, quantitative analysis of the cyclophosphamide metabolites 4-hydroxycyclophosphamide (2a) and aldophosphamide (3a) because these tautomers are generally believed to play a key role in oncostatic selectivity and metabolite transport. O-(2,3,4,5,6-Pentafluorobenzyl)hydroxylamine (C6F5CH2ONH2, 1 equiv) provided for the complete conversion (by 31P NMR, 60% reaction within 15 min at 20 degrees C) of 2a/3a (17 mM in H2O/CH3OH) to E/Z-aldophosphamide O-(2,3,4,5,6-pentafluorobenzyl)oxime [C6F5CH2ON = CHCH2CH2OP-(O)(NH2)N(CH2CH2Cl)2; E:Z = 54:46 (+/- 3% average deviation)]. Under these conditions, the oxime exhibited little (6%) decomposition over 3 weeks. Parallel studies showed that 4-hydroxyifosfamide/aldoifosfamide reacted completely to give the analogous aldoifosfamide oxime [C6F5CH2ON = CHCH2CH2OP(O)(NHCH2CH2Cl)2; E:Z = 52:48 (+/- 1% average deviation)] with 50% reaction within 15 min at 20 degrees C with no product decomposition over 3 weeks. In aqueous methanol and with 2 equiv C6F5CH2ONH2, clinically useful 4-hydroperoxycyclophosphamide (10 mM; tau 1/2 = 10 min, 37 degrees C) and its isomer 4-hydroperoxyifosfamide (10 mM; tau 1/2 = 25 min, 20 degrees C) underwent complete conversion to the corresponding aldehyde oximes. Each oxime was synthesized with deuterium in the chloroethyl moieties for use as internal standards in GC/MS applications.

Cyclophosphamide↗

PubMed1995

Expression of the betaine aldehyde dehydrogenase gene in barley in response to osmotic stress and abscisic acid.

When subjected to salt stress or drought, some vascular plants such as barley respond with an increased accumulation of the osmoprotectant glycine betaine (betaine), being the last step of betaine synthesis catalyzed by betaine aldehyde dehydrogenase (BADH). We report here cloning and characterization of BADH cDNA from barley, a monocot, and the expression pattern of a BADH transcript. An open reading frame of 1515 bp encoded a protein which showed high homology to BADH enzymes present in other plants (spinach and sugar-beet) and in Escherichia coli. Transgenic tobacco plants harboring the clone expressed high levels of both BADH protein and its enzymatic activity. Northern blot analyses indicated that BADH mRNA levels increased almost 8-fold and 2-fold, respectively, in leaves and roots of barley plants grown in high-salt conditions, and that these levels decreased upon release of the stress, whereas they did not decrease under continuous salt stress. BADH transcripts also accumulate in response to water stress or drought, indicating a common response of the plant to osmotic changes that affect its water status. The addition of abscisic acid (ABA) to plants during growth also increased the levels of BADH transcripts dramatically, although the response was delayed when compared to that found for salt-stressed plants. Removal of plant roots before transferring the plants to high-salt conditions reduced only slightly the accumulation of BADH transcripts in the leaves.

Abscisic Acid↗