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Biomedical subjects

Y C Lee

Publications and source records attributed to Y C Lee.

At least 127 records · Page 7Linked to original sources
PubMed2000

Developmental patterns of mST3GalV mRNA expression in the mouse: in situ hybridization using DIG-labeled RNA probes.

mST3GalV synthesizes ganglioside GM3, the precursor for simple and complex a- and b- series gangliosides, and the expression and regulation of mST3GalV (CMP-NeuAc: lactosylceramide alpha2,3-sialyltransferase) activity is central to the production of almost all gangliosides, a class of glycosphingolipids implicated in variety of cellular processes such as transmembrane signaling, synaptic transmission, specialized membrane domain formation and cell-cell interactions. To understand the developmental expression of mST3GalV in mice, we investigated the spatial and temporal expression of mST3GalV mRNA during the mouse embryogenesis [embryonic (E) days; E9, E11, E13, E15] by in situ hybridization with digoxigenin-labeled RNA probes. All tissues from E9 and E11 were positive for mST3GalV mRNA. On E13, mST3GalV mRNA was expressed in various neural and non-neural tissues. In contrast to these, on E15, the telencephalon and liver produced a strong expression of mST3Gal V which was a quite similar to that of E13. In this stage, mST3GalV mRNA was also expressed in some non-neural tissues. These data indicate that mST3GalV is differently expressed at developmental stages of embryo, and this may be importantly related with regulation of organogenesis in mice.

Animals↗
PubMed2000

Seizure outcome after corpus callosotomy: the Taiwan experience.

From September 1989 to August 1996, we performed anterior corpus callosotomy in 83 patients. Unfortunately, 9 patients were lost to follow-up. Among the remaining 74 patients, 59 had Lennox-Gastaut syndrome (evolved from infantile spasms in 22), 9 had complex partial seizures with or without secondary generalized seizures, 1 had multifocal independent epileptogenic foci (MISF) syndrome, 3 had hemiconvulsion-hemiplegia-epilepsy (HHE), and 2 had infantile spasms. All cases were followed up for at least 2 years after surgery. The highest rate of significant improvement (more than 50% reduction in seizure frequency) was noted in the patients with generalized tonic-clonic seizures, 82.1% of whom experienced significant improvement, followed by those with generalized tonic seizures (76. 7%), atonic seizures (72.7%), myoclonic seizures (64.9%), atypical absences (58.6%), and complex partial seizure with or without secondary generalization (61.5%). Complete freedom from seizures was noted in 14 cases (18.9%). One patient had the anterior half of his right palm amputated following radial artery thrombosis complicated by insertion of an arterial line during anesthesia. Otherwise, there were no major postoperative complications except for brief mutism and multifocal jerks in some patients during the 1st postoperative week. Thus, we conclude that corpus callosotomy is a safe alternative treatment for all kinds of medically intractable seizures, especially generalized epilepsy.

Adolescent↗
PubMed2000

Usefulness of pig-tail catheter for palliative drainage of malignant pleural effusions in cancer patients.

We retrospectively collected data from patients enrolled between 1996 and 1997, to evaluate the efficacy of sono-guided pig-tail-catheter drainage in cancer patients with large, symptomatic, amounts of malignant effusion and to evaluate the hemodynamic change after effusion drainage. A total of 477 pig-tail catheter drainage procedures were performed on 342 cancer patients. Sonographic findings, volume drained within 36 h after pig-tail insertion, heart rate and respiratory rate 24 h before and after drainage, and dyspnea sensations were recorded. We found that unilateral right-side effusion was the most frequent presentation. The mean amount of effusion drained within 36 h was 1,747 ml in cancer patients. The decreases in heart rate (from 97/min to 91/min) and in respiratory rate (from 23/min to 21/min) were both statistically significant. There was no significant correlation between the amount of effusion before drainage and the heart rate or respiratory rate. The amount drained within 36 h was correlated significantly with the changes in heart and respiratory rates. Dyspnea sensations decreased or subsided in 91% of the patients within this time period. There were few complications with the pig-tail drainage procedure. Sono-guided pig-tail drainage is a safe and convenient method of effusion drainage in cancer patients. It not only provides temporary relief of symptoms from massive pleural effusions, but can also be used for pleurodesis if needed.

Adolescent↗
PubMed2000

Angiogenesis in early-invasive and low-malignant-potential epithelial ovarian carcinoma.

OBJECTIVE: To evaluate angiogenesis in ovaries of women with stage I invasive and low-malignant-potential epithelial ovarian carcinoma. METHODS: Ovarian specimens of 49 consecutive women with primary stage I invasive (n = 15) or stage I low-malignant-potential epithelial ovarian carcinoma (n = 34) were stained immunohistochemically for factor VIII-related antigen. Microvessel counts were tested for correlation with patient age, race, parity, previous oral contraceptive use, histologic type, tumor grade, tumor size, ascites, tumor excrescences, and disease-free and overall survival. Statistical analysis included multiple linear regression, Student t tests, factorial analysis of variance, and Cox proportional hazards regression, with P <.05 considered statistically significant. RESULTS: Microvessel counts of ovarian specimens of women with stage I invasive epithelial ovarian carcinoma (median 30, range 17-73) were significantly higher than those of women with stage I low-malignant-potential epithelial ovarian carcinoma (median 10, range 5-23), (P <.001). Among women with low-malignant-potential disease, microvessel counts did not differ significantly between serous and mucinous carcinomas (median 10, range 5-23 versus median 11, range 5-20, respectively, P =.78). There was no correlation between microvessel counts and age, tumor grade, tumor size, ascites, or tumor excrescences. CONCLUSION: Angiogenesis as assessed by microvessel counts is more intense in stage I invasive ovarian epithelial carcinoma compared with stage I low-malignant-potential carcinoma, and might assist in differentiating between these histopathologic entities.

Adolescent↗
PubMed2000

Cellular signaling with nitric oxide and cyclic guanosine monophosphate.

The understanding of the formation and biological actions of nitric oxide (NO) has grown extensively during the past two decades. With the discoveries of the biological effects of NO and nitrovasodilators on cyclic guanosine monophosphate, with the elucidation of the biochemical mechanisms of NO synthesis, and with the growing knowledge of regulation of NO synthases, the complexities of this signal transduction cascade and its participation in numerous cell signaling processes continues. NO can be recognized as an intracellular second messenger, a local substance for regulation of neighboring cells, a neurotransmitter, and probably a hormone acting at distant sites.

Animals↗
PubMed2000

Effect of dietary Platycodon grandiflorum on the improvement of insulin resistance in obese Zucker rats.

The effect of dietary Platycodon grandiflorum on the improvement of insulin resistance and lipid profile was investigated in lean (Fa/-) and obese (fa/fa) Zucker rats, a model for noninsulin dependent diabetes mellitus. Dietary Platycodon grandiflorum feeding for 4 weeks resulted in a significant decrease in the concentration of plasma triglyceride in both lean and obese Zucker rats. Furthermore, dietary Platycodon grandiflorum markedly decreased both plasma cholesterol and fasting plasma insulin levels, and significantly decreased the postprandial glucose level at 30 min during oral glucose tolerance test in obese Zucker rats. Although there was no statistical significance, the crude glucose transporter 4 protein level of obese rats fed Platycodon grandiflorum tended to increase when compared with that of obese control rats. Therefore, the present results suggested that dietary Platycodon grandiflorum may be useful in prevention and improvement of metabolic disorders characterized by hyperinsulinemia states such as noninsulin dependent diabetes mellitus, syndrome X, and coronary artery disease.

Journal Article↗
PubMed2000

The correlations between the difficult temperament and subjective psychiatric symptoms in Chinese early adolescents.

This study was designed to assess the intercorrelations between difficult temperament factors and self-rating psychiatric symptoms in Chinese early adolescents. The study subjects completed the Chinese Adolescent Temperament Self-Rating Questionnaire and Brief Psychiatric Symptom Rating Scale. Results revealed that the group of subjects with two or more difficult temperament factors showed significantly higher scores in some of self-rating psychiatric symptoms. In addition to difficult temperament factors, low score of task orientation and tactile threshold also appeared to be risk factors for self perceived psychiatric symptoms in the Chinese adolescents.

Adolescent↗
PubMed2000

Gene polymorphisms of endothelial nitric oxide synthase and angiotensin-converting enzyme in patients with asthma.

BACKGROUND: Nitric oxide, including that produced by endothelial constitutive nitric oxide synthase (ecNOS), may regulate vascular and airway tone in the lungs and may influence various aspects of airway homeostasis. Angiotensin-converting enzyme (ACE) is expressed at high levels in the lungs and plays a role in the metabolism of angiotensin II, bradykinin, and substance P, all of which are potentially involved in the pathogenesis of asthma. An insertion-deletion polymorphism of the ACE gene has been shown to be associated with enzyme activity levels of ACE. To examine the possible involvement of the ecNOS and/or ACE genes as the genetic basis of bronchial asthma, we investigated whether there was any association between bronchial asthma and polymorphisms of the ecNOS and/or ACE genes. METHODS: A total of 310 patients with bronchial asthma and 121 healthy subjects took part in this study. The ecNOS and ACE genotypes were determined in all subjects by polymerase chain reaction. RESULTS: 1) The distribution of one genotype (bb) of ecNOS was significantly higher in the asthma group than in the control population. 2) The ACE genotype distribution was not significantly different between the control and the asthma groups. 3) In asthmatic patients, the ACE and ecNOS genotype distribution did not differ significantly among groups of patients with different severities of asthma. CONCLUSIONS: These results suggest that polymorphisms of the ecNOS gene, but not the ACE gene, may be associated with the development of asthma. However, the severity of asthma may not be influenced by polymorphisms of the ecNOS and ACE genes.

Adult↗
PubMed2000

alpha3-galactosylated glycoproteins can bind to the hepatic asialoglycoprotein receptor.

In mammals, clearance of desialylated serum glycoproteins to the liver is mediated by a galactose-specific hepatic lectin, the 'asialoglycoprotein receptor'. In humans, serum glycoprotein glycans are usually capped with sialic acid, which protects these proteins against hepatic uptake. However, in most other species, an additional noncharged terminal element with the structure Galalpha1-->3Galbeta1-->4R is present on glycoprotein glycans. To investigate if alpha3-galactosylated glycoproteins, just like desialylated glycoproteins, could be cleared by the hepatic lectin, the affinities of alpha3-galactosylated compounds towards this lectin were determined using an in vitro inhibition assay, and were compared with those of the parent compounds terminating in Galbeta1-->4R. Diantennary, triantennary and tetraantennary oligosaccharides that form part of N-glycans were alpha3-galactosylated to completion by use of recombinant bovine alpha3-galactosyltransferase. Similarly, desialylated alpha1-acid glycoprotein (orosomucoid) was alpha3-galactosylated in vitro. The alpha3-galactosylation of a branched, Galbeta1-->4-terminated oligosaccharide lowered its affinity for the membrane-bound lectin on whole rat hepatocytes 50-250-fold, and for the detergent-solubilized hepatic lectin 7-50-fold. In contrast, alpha3-galactosylation of asialo-alpha1-acid glycoprotein caused only a minor decrease in affinity, increasing the IC50 from 5 to 15 nM. Fully alpha3-galactosylated alpha1-acid glycoprotein, intravenously injected into the mouse, was rapidly cleared from the circulation, with a clearance rate close to that of asialo-alpha1-acid glycoprotein (t1/2 of 0.42 min vs. 0.95 min). Its uptake was efficiently inhibited by pre-injection of an excess asialo-fetuin. Organ distribution analysis showed that the injected alpha1-acid glycoprotein accumulated predominantly in the liver. Taken together, these observations suggest that serum glycoproteins that are heavily alpha3-galactosylated will be rapidly cleared from the bloodstream via the hepatic lectin. It is suggested that glycosyltransferase expression in murine hepatocytes is tightly regulated in order to prevent undesired uptake of hepatocyte-derived, circulating glycoproteins.

Animals↗
PubMed2000

Epileptic seizures in a patient by immersing his right hand into hot water.

We report on a 22-year-old assistant cook, presenting with seizures evoked by immersing his right hand into hot water of 40-46 degrees C. His seizure pattern consisted of either simple partial seizures of a tingling sensation arising in the right hand and marching to the right shoulder or a similar attack evolving to a complex partial seizure. Video-EEG monitoring recorded habitual seizures originating from the left centro-temporo-parietal region, compatible with lesions seen on brain magnetic resonance imaging. He responded well to antiepileptic drug treatment and wearing gloves while working in the kitchen. In this patient, hot water of 40-46 degrees C could maximally stimulate skin warm thermoreceptors in the right hand whereby afferent impulses subsequently activated the epileptogenic focus, adjacent to or in the sensory cortex, and elicited seizures.

Adult↗
PubMed2000

Use of esophagectomy to treat recurrent hyperplastic tissue obstruction caused by multiple metallic stent insertion for corrosive stricture.

We report a case of a 75-year-old woman who received repeated metallic stent insertion for corrosive esophageal injury. She underwent esophagectomy and gastric tube reconstruction about 3 years after injury because both stents were occluded in turn by overgrowth of granulation tissue. The gross and microscopic changes of the esophagus secondary to prolonged stent insertion are described. In the literature, no reports of similar cases have been recorded. Our limited experience revealed that using metallic stents to treat benign esophageal stricture should be handled very cautiously because of the complications which can commonly occur and are difficult to manage. Repeated stent insertion, although effective for temporarily relieving dysphagia, is ineffective in the long run and can create complications. We suggest that the feasibility of esophagectomy should be evaluated after the improvement of the general condition of the patient.

Aged↗
PubMed2000

E-cadherin expression in surgically-resected non-small cell lung cancers--a clinicopathological study.

BACKGROUND: E-Cadherin is a subclass of the cadherin family that plays a major role in the maintenance of intercellular junctions in normal epithelium. Decreased expression of E-cadherin might be closely related to invasiveness and dedifferentiation in human cancers. This study is aimed at investigating the clinicopathological significance of E-cadherin expression and its impact on the prognosis in surgically resected non-small-cell lung cancer patients. METHODS: Using immunohistochemical staining, the expression of E-cadherin was studied in 207 surgically resected lung cancer specimens from January 1990 through December 1994. The clinicopathological data and survival status were recorded and analysed against the E-cadherin expression level in each tumor. RESULTS: E-cadherin expression was detected in 122 of the 207 lung tumors (59.0%), and the expression was significantly lower in tumors with poor differentiation (p < 0.001), in tumors with vascular invasion (p < 0.05), and in tumors with direct invasion into surrounding structures (p < 0.01). There was no correlation between E-cadherin expression, and tumor stage and regional lymph-node metastasis. There was no significant difference in survival rate between higher (> 40%) and lower (< 40%) E-cadherin expression groups; however, in tumors 3 cm or less, a significant difference was found between higher and lower E-cadherin expressions (p < 0.0001). CONCLUSIONS: Underexpression of E-cadherin is associated with poor differentiation and invasiveness in NSCLC. In patients with small NSCLC (< or = 3 cm), higher E-cadherin expression (> 40%) significantly had a favorable prognosis.

Adult↗
PubMed2000

Ocular gelfoam disc-applicator for pupillary dilation in humans.

This study investigates a gelfoam disc device as an alternative topical ophthalmic drug delivery system for pupillary dilation in humans. Gelfoam (Pharmacia & Upjohn) discs were impregnated with 0.60 mg of tropicamide racemate and 1.7 mg of 1-phenylephrine hydrochloride by an ethanol solvent evaporation method. Twenty randomly selected human subjects received baseline examinations, including blood pressure, pulse rate and biomicroscopy of the ocular surface. One impregnated gelfoam disc was placed in the inferior fornix of a randomly selected eye. Simultaneously, the fellow eye was treated with two topically administered drops, one from a phenylephrine hydrochloride 2.5% solution and one from a tropicamide 1% solution. A single, masked observer measured the pupillary diameter in both eyes at various time intervals under constant ambient conditions. Administration of the topical drops was repeated in the fellow eye. At maximum pupillary dilation, the disc was removed, and a post-dilation biomicroscopic exam was performed. Blood pressure and pulse rate were rechecked. The gelfoam-treated eyes' median change in dilation diameter was approximately 25% greater (a two-fold increase in pupillary area) (p< 0.001) at 15.2 min (median time to maximum dilation) than the topically treated fellow eyes. The median change in systolic blood pressure (+1.0 mmHg) and diastolic blood pressure (-1.0 mmHg) was not statistically significant (p>0.1). The average pulse rate was decreased 7 beats per minute (p=0.004). A gelfoam disc may serve as an ophthalmic drug delivery system for pupillary dilation or as a model for other multiple-dose topical drugs.

Adult↗
PubMed2000

Photoaffinity glycoprobes-a new tool for the identification of lectins.

One of the proposed functions for the carbohydrate structures on glycoconjugates is the transfer of information through interaction with specific lectin receptors. However, the number of elucidated functional lectin-carbohydrate interactions is still relatively small, largely due to the lack of adequate methods to identify lectin activity in complex biological samples. Aiming to solve this problem, we have developed a method based on the novel group of compounds we named glycoprobes. The glycoprobe consists of three vital parts: (1) glycan, (2) digoxin tag, and (3) photoreactive crosslinker. When incubated in dark, oligosaccharide part of the glycoprobe forms a complex with lectin. After illumination, covalent link between the probe and the lectin is formed resulting in a digoxin-tagged lectin. Using antibodies against digoxin, this complex can easily be identified immuno/cytochemically, or by Western blots. To demonstrate the applicability of glycoprobes we have used Man(9)-glycoprobe (containing Man(9)oligosaccharide) and YEE(ahGalNAc)(3)-glycoprobe (containing a synthetic neoglycopeptide with three terminal N-acetyl-galactosamine residues; Lee and Lee, Glycoconjugate J., 1987,4, 317) to identify lectins in bovine serum and rat liver membranes. The simplicity of the method enables its application in routine monitoring of changes in lectin activity during various developmental or pathological processes. An example of GalNAc-binding analysis in human serum is shown.

Acetylgalactosamine↗
PubMed2000

N-glycan patterns of human transferrin produced in Trichoplusia ni insect cells: effects of mammalian galactosyltransferase.

The N-glycans of human serum transferrin produced in Trichopulsia ni cells were analyzed to examine N-linked oligosaccharide processing in insect cells. Metabolic radiolabeling of the intra- and extracellular protein fractions revealed the presence of multiple transferrin glycoforms with molecular weights lower than that observed for native human transferrin. Consequently, the N-glycan structures of transferrin in the culture medium were determined using three-dimensional high performance liquid chromatography. The attached oligosaccharides included high mannose, paucimannosidic, and hybrid structures with over 50% of these structures containing one fucose, alpha(1,6)-, or two fucoses, alpha(1,6)- and alpha(1,3)-, linked to the Asn-linked N-acetylglucosamine. Neither sialic acid nor galactose was detected on any of the N-glycans. However, when transferrin was coexpressed with beta(1,4)-galactosyltransferase three additional galactose-containing hybrid oligosaccharides were obtained. The galactose attachments were exclusive to the alpha(1, 3)-mannose branch and the structures varied by the presence of zero, one, or two attached fucose residues. Furthermore, the presence of the galactosyltransferase appeared to reduce the number of paucimannosidic structures, which suggests that galactose attachment inhibits the ability of hexosaminidase activity to remove the terminal N-acetylglucosamine. The ability to promote galactosylation and reduce paucimannosidic N-glycans suggests that the oligosaccharide processing pathway in insect cells may be manipulated to mimic more closely that of mammalian cells.

Animals↗
PubMed2000

A phase II study of single-agent docetaxel chemotherapy for non-small cell lung cancer.

BACKGROUND: Docetaxel is an active agent used in the treatment of non-small cell lung cancer (NSCLC). METHODS: A phase II trial of single-agent docetaxel chemotherapy was conducted in Chinese patients with NSCLC, as either a first- or second-line treatment, to assess response and toxicity. The treatment scheme was docetaxel 75 mg/m2 intravenous infusion for 1 h every 3 weeks for up to nine cycles. Dexamethasone was routinely given for 3 days, beginning 1 day before chemotherapy. RESULTS: From August 1996 to December 1997, 48 patients were enrolled, including 34 chemo-naive patients and 14 patients previously treated with one chemotherapeutic regimen. All patients were evaluable for toxicity profiles and 47 patients were evaluable for response rate. As expected, the major toxicity was myelosuppression. Grade 3 or 4 neutropenia occurred in 41 of 48 (85.5%) patients during treatment. Twenty patients (41.7%) experienced febrile neutropenia and accounted for two toxic deaths. Only one patient suffered from grade 3 thrombocytopenia and two patients from grade 3 anemia. Moderate or severe asthenia occurred in 30 patients (62.5%). Moderate fluid retention (peripheral edema) was observed in five patients (10.4%) and severe fluid retention in three; all were reversible. No grade 3 or 4 neurosensory toxicity was observed. After two cycles of treatment, 14 of 47 evaluable patients attained a partial response (29.8%, 95% CI 16.7-42.9%), including 30.3% (95% CI 14.6-46%) of those in first-line treatment and 28.6% (95% CI 4.9-52.3%) of those in second-line treatment. The median time to disease progression was 13 weeks in first-line patients and 19 weeks in second-line patients. Median survival time was 7.1 and 11.7 months in first- and second-line patients, respectively. CONCLUSION: Docetaxel is active and has an acceptable toxicity profile, in both first- and second-line treatments, in Chinese patients with inoperable NSCLC.

Adenocarcinoma↗