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Biomedical subjects

L Y Han

Publications and source records attributed to L Y Han.

51 records · Page 3Linked to original sources
PubMed1990

In vitro and in vivo effects of ribavirin on human respiratory epithelium.

The effects of ribavirin, a broad spectrum antiviral agent, on the structure and function of normal human nasal epithelium have been studied in vitro, as has also the in vivo effect of treatment with nebulised ribavirin on nasal mucociliary clearance of saccharin in four patients. Ciliary beat frequency was measured by a photometric technique, and changes in epithelial and ciliary ultrastructure were assessed by transmission electron microscopy. Ribavirin solution at the recommended concentration of 20 mg/ml had no adverse effects on ciliary activity in vitro; at concentrations of 50 mg/ml and above it slowed ciliary beating significantly and at 60 mg/ml caused ciliostasis associated with epithelial disruption. Nasal inhalation of ribavirin at 60 mg/ml for up to 20 minutes, however, did not slow nasal mucociliary clearance, nor did it adversely affect the ciliary beating or structure of nasal ciliated epithelium examined in vitro immediately after inhalation.

Aged↗
PubMed1989

Microwave: an alternative to electric heating in the treatment of peripheral lymphedema.

The results of a new method of treating chronic lymphedema with heat, using microwaves, are described in 98 patients with peripheral lymphedema. Thirteen had bilateral lymphedema and were included only to provide additional evidence of the lack of side-effects using this technique. The remaining 85 patients showed a significant (p less than .001) reduction in the amount of peripheral edema with edema reduction greater than 50% in three-fourths of the patients. The incidence and severity of secondary acute inflammation ("erysipelas") were also sharply reduced (p less than .001). The microwave method of heat application has a number of advantages over an older technique which used electrically-powered heating elements.

Arm↗
PubMed1985

Venous versus lymphatic duct autotransplantation in the treatment of experimental lymphedema.

Experimental autologous lymphatic duct transplantation is technically feasible and therapeutically effective in the treatment of chronic lymphedema of the extremity. However, we demonstrate that the risk of inducing lymphedema in the donor limb is evident; therefore, the clinical application of lymphatic transplantation is compromised. To obviate this risk, a vein graft was substituted in experimental animals with good prophylactic results. Postoperative lymphangiography showing free passage of contrast media through the interposed vein, rapid disappearance of acute lymphedema in the recipient limb (28.6%), and no risk of inducing lymphedema of the donor limb all favor the possibility of using a vein graft transfer in clinically treating chronic lymphedema of the extremity.

Acute Disease↗
PubMed1985

Experimental model of chronic limb lymphedema and determination of lymphatic and venous pressures in normal and lymphedematous limbs.

Experimental studies on chronic lymphedema of the extremities were performed using dogs, and an improved technique after the method of Danese in the preparation of chronic limb lymphedema is described. The incidence of chronic lymphedema in this model was 81.8%, whereas with Danese's method, it was only 66.7%. In addition, the measurement of lymphatic and venous pressure was studied in experimental animals. In the normal limb, the lymphatic pressure was always lower than the venous pressure, while in the chronic lymphedematous limb, the lymphatic pressure was higher than the venous pressure. Thus, after a lymphaticovenous anastomosis, a pressure gradient reversal exists between the two sides of the anastomosis. Although the high lymphatic pressure gradually dropped as the anastomosis became patent, ultimately the venous pressure was often higher than the lymphatic pressure. A venous back flow can be ensured by the anastomosis and the resulting thrombosis, which obstructs the lymphaticovenous anastomosis, is inevitable.

Animals↗
PubMed1978

The involvement of phosphatidate phosphohydrolase and phospholipase A activities in the control of hepatic glycerolipid synthesis. Effects of acute feeding with glucose, fructose, sorbitol, glycerol and ethanol.

Rats were fed by stomach tube with a single dose of glucose, sorbitol, fructose, glycerol or ethanol of equivalent energy contents or with 0.15 M-NaCl. They were killed 6 h later and the relative rates of phosphatidate deacylation and dephosphorylation measured in the microsomal and supernatant fractions of the livers. Treatment with sorbitol, fructose, glycerol and ethanol increased phosphohydrolase activities in the microsomal and supernatant fractions. The only significant change in deacylase activity was an increase in the microsomal fraction produced by ethanol. It is proposed that hepatic triacylglycerol synthesis is partly controlled by the balance between phosphatidate phosphohydrolase and phospholipase A-type activities.

Animals↗
PubMedDate not supplied

Quantitative neurohistological features of frontotemporal degeneration.

Frontotemporal degeneration (FTD) is a neurodegenerative condition that has been principally associated with frontal lobe dementia. In this study, we compared neuropathological abnormalities in frontal, hippocampal, and calcarine cortices from patients assigned a diagnosis of FTD, normal elderly and Alzheimer's disease (AD). Densities of Nissl-stained neurons and lesions which were immunolabeled for tau, beta-amyloid (Abeta), alpha- and beta-synuclein, ubiquitin, glial fibrillary acidic protein (GFAP) and CD68 antigen were determined using computer-assisted, non-biased quantitative microscopy. We found that FTD frontal and hippocampal regions exhibited marked neuron loss, abundant ubiquitin-immunoreactive (ir) dystrophic neurites, GFAP-ir astrocytes, and CD68-ir microglia, while calcarine cortex was spared. No alpha- or beta-synuclein-ir lesions were observed, and neither the density of tau-ir neurofibrillary tangles nor that of Abeta-ir plaques in FTD exceeded normal controls. In addition, there were no neuropathological differences between FTD subjects who presented clinically with a frontal lobe dementia versus an AD-like dementia. These findings indicate that FTD is a category of neurodegnerative dementias with varying clinical presentations that is characterized by the progressive degeneration of select populations of cortical neurons. The molecular neurodegenerative mechanisms that lead to FTD remain to be elucidated.

Aged↗
PubMedDate not supplied

PEARLS: program for energetic analysis of receptor-ligand system.

Analysis of the energetics of small molecule ligand-protein, ligand-nucleic acid, and protein-nucleic acid interactions facilitates the quantitative understanding of molecular interactions that regulate the function and conformation of proteins. It has also been extensively used for ranking potential new ligands in virtual drug screening. We developed a Web-based software, PEARLS (Program for Energetic Analysis of Ligand-Receptor Systems), for computing interaction energies of ligand-protein, ligand-nucleic acid, protein-nucleic acid, and ligand-protein-nucleic acid complexes from their 3D structures. AMBER molecular force field, Morse potential, and empirical energy functions are used to compute the van der Waals, electrostatic, hydrogen bond, metal-ligand bonding, and water-mediated hydrogen bond energies between the binding molecules. The change in the solvation free energy of molecular binding is estimated by using an empirical solvation free energy model. Contribution from ligand conformational entropy change is also estimated by a simple model. The computed free energy for a number of PDB ligand-receptor complexes were studied and compared to experimental binding affinity. A substantial degree of correlation between the computed free energy and experimental binding affinity was found, which suggests that PEARLS may be useful in facilitating energetic analysis of ligand-protein, ligand-nucleic acid, and protein-nucleic acid interactions. PEARLS can be accessed at http://ang.cz3.nus.edu.sg/cgi-bin/prog/rune.pl.

Computer Simulation↗
PubMedDate not supplied

Prediction of functional class of the SARS coronavirus proteins by a statistical learning method.

The complete genome of severe acute respiratory syndrome coronavirus (SARS-CoV) reveals the existence of putative proteins unique to SARS-CoV. Identification of their function facilitates a mechanistic understanding of SARS infection and drug development for its treatment. The sequence of the majority of these putative proteins has no significant similarity to those of known proteins, which complicates the task of using sequence analysis tools to probe their function. Support vector machines (SVM), useful for predicting the functional class of distantly related proteins, is employed to ascribe a possible functional class to SARS-CoV proteins. Testing results indicate that SVM is able to predict the functional class of 73% of the known SARS-CoV proteins with available sequences and 67% of 18 other novel viral proteins. A combination of the sequence comparison method BLAST and SVMProt can further improve the prediction accuracy of SMVProt such that the functional class of two additional SARS-CoV proteins is correctly predicted. Our study suggests that the SARS-CoV genome possibly contains a putative voltage-gated ion channel, structural proteins, a carbon-oxygen lyase, oxidoreductases acting on the CH-OH group of donors, and an ATP-binding cassette transporter. A web version of our software, SVMProt, is accessible at http://jing.cz3.nus.edu.sg/cgi-bin/svmprot.cgi .

Adenosine Triphosphate↗
PubMedDate not supplied

A gelatin matrix-thrombin tissue sealant (FloSeal) application in the management of groin breakdown after inguinal lymphadenectomy for vulvar cancer.

The rate of groin breakdown after radical wide vulvar excision and inguinal lymphadenectomy for vulvar cancer remains significant despite conservative surgical approaches. An 86-year-old Latin American woman underwent wide radical excision and bilateral inguinal lymphadenectomy for vulvar cancer. The postoperative course was complicated by bilateral groin wound separation and high output lymphorrhea. The patient responded to the application of a gelatin matrix-thrombin tissue sealant (FloSeal) to the bases of each groin with resolution in lymphorrhea and formation of granulation tissue. The application of a gelatin matrix-thrombin tissue sealant (FloSeal) may be a viable treatment in the management of groin breakdown in selected patients when conventional therapy produces suboptimal results.

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