Search PubMed⌕ Search

Biomedical subjects

S J Hwang

Publications and source records attributed to S J Hwang.

At least 19 recordsLinked to original sources
PubMed2006

Controlled delivery of a hydrophilic drug from a biodegradable microsphere system by supercritical anti-solvent precipitation technique.

The purpose of this study was to prepare microspheres loaded with hydrophilic drug, bupivacaine HCl using poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). Microspheres were prepared with varying the PLGA/PLLA ratio with two different levels of bupivacaine HCl (5 and 10%) using a supercritical anti-solvent (SAS) technique. Microspheres ranging from 4-10 microm in geometric mean diameter could be prepared, with high loading efficiency. Powder X-ray diffraction (PXRD) revealed that bupivacaine HCl retained its crystalline state within the polymer and was present as a dispersion within the polymer phase after SAS processing. The release of bupivacaine HCl from biodegradable polymer microspheres was rapid up to 4 h, thereafter bupivacaine HCl was continuously and slowly released for at least 7 days according to the PLGA/PLLA ratio and the molecular weight of PLLA.

Absorbable Implants↗
PubMed2006

The prescriptions frequencies and patterns of Chinese herbal medicine for allergic rhinitis in Taiwan.

BACKGROUND: The evaluation of Chinese herbal medicines (CHM) to allergic rhinitis (AR) by large-scale pharmaco-epidemiological study is not ease found, although CHM had been reported to have potential effect for AR in some clinical trials. AIMS OF THE STUDY: To explore the frequency and pattern of CHM prescriptions on AR, we have the study by analysing the population-based CHM database in Taiwan. METHODS: The way for this study was linked and processed the complete traditional Chinese medicine database for Taiwanese recorded in the year 2002. The diagnosis of AR was extracted with the only single ICD-9 Code of 477 to calculate the frequency and pattern of prescriptions. Association rule was applied to analyse co-prescription of CHM for patients with AR. RESULTS: In the year 2002, among the 22 520 776 valid beneficiaries of the National Health Insurance, Taiwan, 914 612 subjects (3.8% of the total valid beneficiaries) have diagnosed AR. There were 35.6% of AR patients been treated by CHM. The peak age of AR patients treated by CHM was at the first decade (0-10). For the AR patients, the most common Chinese herbal formula prescription was Shin-yi-qing-fei-tang, or Angelica dahurica (Bai-zhi) for the single Chinese herb. While for the combination treatments the most common prescription was the two formulae, Xiao-qing-long-tang and Shin-yi-san. CONCLUSIONS: Because of the high utilization rate of the CHM treatment for AR, a large-scale randomized trial warrants further research for its efficacy and safety.

Adolescent↗
PubMed2006

Endothelin-1 regulates parathyroid hormone expression of human parathyroid cells.

OBJECTIVE: Parathyroid cells synthesize and release endothelin-1 (ET-1). ET-1 displays an in vitro inhibitory effect on basal parathyroid hormone (PTH) secretion and also counteracts PTH hypersecretion stimulated by low calcium. Such effects are further demonstrated in vivo, independent of the changes in calcitonin. We propose that ET-1 may regulate the pathogenesis of uremic hyperparathyroidism. However, this was not directly demonstrated in human parathyroid glands. DESIGN: Hyperplastic parathyroid glands are obtained from the surgical operation for uremic hyperparathyroidism. Cells are isolated by enzyme digestion and treated with ET-1, and are assessed for PTH mRNA expression. PTH in the plasma and the medium is measured by a newly developed method to detect the whole PTH (1-84). PATIENTS: Uremic patients with severe secondary hyperparathyroidism and ultrasonography-proved hypertrophy of parathyroid glands received elective surgical approaches under general anesthesia. The resected glands were immediately taken to the laboratory for fresh isolation. MEASUREMENTS: Following ET-1 treatment, PTH mRNA expression is evaluated by RT-PCR method. ET-1 is detected with radioimmunoassay kit and PTH is measured by a new commercially available Duo PTH kit. RESULTS: ET-1 exhibited a dose-dependent inhibitory effect (from 10(-12) - 10(-7) M) on PTH mRNA expression of parathyroid cells, either in the basal or in the low-calcium-stimulated states. Release of PTH into the medium is also gradually inhibited by the increase in ET-1 concentrations. CONCLUSIONS: Our results demonstrate that ET-1 attenuates PTH mRNA expression in freshly isolated human parathyroid cells, and PTH release is also decreased. This result is consistent with our previously reported in vitro and in vivo experiments.

Adult↗
PubMed2006

Decreased B cells and IgA-secreting B cells partially explain the high prevalence of IgA deficiency in dialysis patients.

AIMS: We previously reported 2 hemodialysis (HD) patients with recurrent infections and selective immunoglobulin A deficiency (IgAD). We further demonstrated that serum IgA levels were lower and the prevalence of IgAD was higher in uremic patients. The exact mechanisms of IgAD in uremic patients largely remained unclear. In some patients, it was caused by anti-IgA antibody neutralization and subsequent destruction. We performed the present study to survey if there is any defect in IgA production. MATERIALS AND METHODS: 288 patients were initially included for examination of serum immunoglobulins. 16 normal persons, 16 dialysis patients without IgAD, and 12 dialysis patients with IgAD were enrolled after the initial examination. Blood was drawn into heparinized tubes. WBC counts and lymphocyte percentage were examined by a CBC counter. Lymphocytes were separated by the Ficoll-Paque method. Flow cytometry was utilized to isolate the B cell and IgA-secreting B cell after staining with CD 19 phycoerythrin and FITC-conjugated rabbit anti-human IgA antibody. RESULTS: There is no significant difference between WBC counts or total lymphocyte counts of these 3 groups. However, we found a lower percentage of total lymphocyte counts in dialysis patients, either with or without IgAD. The total B cell numbers were lower in dialysis patients with IgAD. In addition, there were fewer IgA-secreting B cells in dialysis patients with IgAD. CONCLUSION: Decreased B cell and IgA-secreting B cell counts are seen in uremic patients with IgAD. This, in turn, indicates that there might be a defect of IgA production in some patients, rather than IgA destruction by anti-IgA antibodies as seen in some other patients. Further study is needed to investigate the mechanisms of decreased B cells and IgA-secreting B cells.

Adult↗
PubMed2005

Characteristics of felodipine-located poly(epsilon-caprolactone) microspheres.

Felodipine-loaded poly (epsilon-caprolactone) (PCL) microspheres were prepared by two methods, the conventional emulsion solvent evapouration method and the quenching method. The aim of this work was to investigate the effects of process parameters such as emulsion type, drug loading, molecular-weight of the polymer, types of emulsion stabilizer and dispersed phase solvents, as well as preparation methods. The results show that, when conventional emulsion solvent evapouration method was used, the o/w-method produced smaller mean size and higher encapsulation efficiency compared with the o/o-method. The encapsulation efficiencies increased with an increase in the molecular weight and a decrease in crystallinity of PCL. The size of microspheres varied with the type of emulsion stabilizer used, smaller microspheres with PVA and narrow size distribution with Pol 237. The water solubility of the dispersed phase solvent was one of the critical factors in controlling the encapsulation efficiency and microsphere mean size. When water-soluble solvents such as acetonitrile and ethyl formate were used, the encapsulation efficiencies decreased due to higher evapouration rate. When quenching methods were used, in contrast to the conventional emulsion solvent evapouration method, very narrowly size-distributed but bigger microspheres were obtained.

Antihypertensive Agents↗
PubMed2004

Acquired syngnathia.

We report two cases of acquired syngnathia, in case 1 probably as a result of a fibrotic tubed pedicle and in case 2 from myositis ossificans. The treatment plan for syngnathia must include not only operation but also a rehabilitation programme (particularly muscle training)

Child, Preschool↗
PubMed2004

Neuropeptide Y immunoreactivity and corticotropin-releasing hormone mRNA level are increased in the hypothalamus of mouse bearing a human oral squamous cell carcinoma.

We examined gene expression of corticotropin-releasing hormone and neuropeptide Y level in the hypothalamic paraventricular nucleus of mouse bearing a human oral squamous cell carcinoma. A cell line derived from a human oral squamous cell carcinoma was inoculated into the lower dorsal area of nude mice. Body weight, tumor size and daily food intake were recorded every morning. Mice were sacrificed for corticotropin-releasing hormone mRNA in situ hybridization and neuropeptide Y immunohistochemistry, when the tumor ratio reached to 11-13% of real body weight. The results were compared with the age-matching non-tumor controls injected with saline instead of carcinoma cell. Body weight gain was significantly reduced in tumor bearing mice, however, no compensatory hyperphagia was found, i.e. daily food intake of the tumor mice did not differ from the non-tumor mice. Both neuropeptide Y immunoreactivity and corticotropin-releasing hormone mRNA level were significantly increased in the hypothalamic paraventricular nucleus of tumor mice. These results suggest that a human oral squamous cell carcinoma may induce anorexia, at least partly, via increasing the hypothalamic expression of corticotropin-releasing hormone in the tumor subjects. Additionally, neuropeptide Y-induced feeding appears to be inhibited in this tumor anorexia model, and this may correlate with increased expression of corticotropin-releasing hormone.

Animals↗
PubMed2004

Concomitant reconstruction of mandibular basal and alveolar bone with a free fibular flap.

Repair of long-span mandibular defects with a free fibular flap is now a routine procedure. However, the bone height of the neo-mandible after reconstruction with a fibular flap is about half that of the dentulous mandible. When a fibular graft is placed only at the inferior border of the mandible, the resulting vertical discrepancy between the graft segment and the occlusal plane can adversely affect implant mechanics or denture stability and retention. To overcome these problems, we developed a technique for two-strut type mandibular reconstruction. A vascularized fibular segment is used to reconstruct the inferior basal portion of the neo-mandible, while a non-vascularized residual fibular segment is used to simulate the superior alveolar portion. We used this technique in 22 patients. Graft survival, graft resorption, and the ability to place implants were assessed as compared with those after the conventional one-strut type technique. The fibular segment grafted to the alveolar region was removed in one patient with intraoral wound dehiscence and in two with postoperative infection. All vascularized fibular flaps were successful. The resorption rate was 13.6+/-7.2% for non-vascularized segments and 3.0+/-3.7% for vascularized segments. Dental implants were placed in five of our 22 patients. The crown:fixture length ratio was improved to 1:1.7, as compared with a ratio of 1:1.21 with use of a conventional fibular flap. We conclude that our technique is very easy and safe and provides substantially improved lower-lip and cheek support and implant-prosthetic mechanics than conventional procedures for the repair of long-span mandibular defects.

Adult↗
PubMed2004

Characteristics of granular sludge in a single upflow sludge blanket reactor treating high levels of nitrate and simple organic compounds.

Simultaneous denitrification and methanogenesis were accomplished in a single upflow sludge blanket (USB) reactor. More than 99% and 95% of nitrate and chemical oxygen demand (COD) removal rates were obtained at a loading of 600 mg NO3-N/L x d and 3,300 mg COD/L x d, respectively. The specific denitrification rate (SDR) increased as COD/NO3-N ratios decreased. Maximum SDR with acetate could reach 1.05 g NO3-N/gVSS x d. Significant sludge flotation was observed at the top of the reactor due to the change of microbial composition and the formation of hollow granules. Granules became fluffy and buoyant due to the growth of denitrifiers. Microscopic examination showed that granules exhibited layered structure and they were mainly composed of Methanosarcina sp., Pseudomonas sp., and rod-shaped bacteria.

Bioreactors↗
PubMed2003

Vanilloid receptor VR1-positive afferents are distributed differently at different levels of the rat lumbar spinal cord.

The vanilloid receptor VR1 renders a group of primary afferents that express it sensitive to noxious heat and capsaicin, and is thus an important marker for nociceptors. We use double immunofluorescence and confocal microscopy to show that the density of VR1-positive fibers and boutons in the dorsal horn increases progressively from spinal segments L4 to L6 and that the colocalization of VR1 with the neuropeptide substance P (SP) in lamina I and along the lateral collateral path, where the majority of visceral afferents terminate, is negligible at L4, but substantial at L6. We conclude that VR1 is expressed by visceral afferents to the lower lumbar spinal cord in the rat, which also express SP.

Animals↗
PubMed2003

Clinical analysis of extranodal non-Hodgkin's lymphoma in the sinonasal tract.

We investigated the clinical analysis of non-Hodgkin's lymphoma (NHL) of the sinonasal tract, including the survival rate and treatment outcome. Fifty patients who had previously received a diagnosis of extranodal NHL of the sinonasal cavity from May 1992 to April 2001 were included. We reviewed the patients' clinical characteristics and the survival rates, retrospectively. Of 50 patients, 49 were classified as having extranodal NK/T cell lymphoma and only one patient as having diffuse large B cell (DLBC) lymphoma according to the new WHO classification. Even though higher mortality rates were observed in patients receiving chemotherapy alone than in those receiving chemotherapy and radiation therapy in the advanced stage, the combination treatment of chemotherapy and radiation therapy failed to demonstrate a significantly higher survival rate.

Adolescent↗
PubMed2003

Trends in prescribing proton pump inhibitors in Taiwan: 1997 - 2000.

OBJECTIVE: The prescribing of proton pump inhibitors (PPIs) had increased greatly in recent years worldwide. Aim of our study was to analyze the utilization patterns of PPIs within the National Health Insurance program in Taiwan from 1997 - 2000. MATERIAL AND METHOD: The systemic sampling data-sets from the National Health Insurance Research Database served as data sources. Units of measurement for PPIs were numbers of prescription items and defined daily doses (DDDs). To estimate the proportion of the population treated daily with PPIs, numbers of DDDs per 1,000 inhabitants per day were calculated. In order to realize the role of PPIs in treating Helicobacter pylori-related disorders, we also analyzed various combined prescriptions of PPIs with amoxicillin, clarithromycin, metronidazole, tetracycline and bismuth. RESULTS: In the study period, PPI prescriptions increased nearly 2-fold at the outpatient sector and more than 3-fold at the inpatient sector. Men received more PPI prescriptions, as a whole, than women. Most PPIs were prescribed at the outpatient sector: 93.9% in 1997, 92.3% in 1998, 90.4% in 1999 and 87.3% in 2000. The numbers of DDDs per 1,000 inhabitants per day for all kinds of PPIs were 0.59, 0.78, 1.07, and 1.13 from 1997 - 2000, respectively. While the percentage of monotherapy increased from 63.6% in 1997 to 75.5% in 2000, the combination therapies did not experience a rapid and sustained growth. Among the combination therapies, PPI + amoxicillin + metronidazole and PPI + amoxicillin were popular in 1997 and 1998, but triple therapy with PPI + amoxicillin + clarithromycin predominated in 1999 and 2000. CONCLUSIONS: Despite increasing use, prescribing volumes of PPIs in Taiwan were far fewer than those in other developed countries. Treatment of Helicobacter pylori-related disorders in Taiwan followed universal standard.

Adult↗
PubMed2002

Preparation and characterization of chitosan microparticles intended for controlled drug delivery.

Chitosan microparticles were prepared with tripolyphosphate (TPP) by ionic crosslinking. The particle sizes of TPP-chitosan microparticles were in range from 500 to 710 microm and encapsulation efficiencies of drug were more than 90%. The morphologies of TPP-chitosan microparticles were examined with scanning electron microscopy. As pH of TPP solution decreased and molecular weight (MW) of chitosan increased, microparticles had more spherical shape and smooth surface. Release behaviors of felodipine as a model drug were affected by various preparation processes. Chitosan microparticles prepared with lower pH or higher concentration of TPP solution resulted in slower felodipine release from microparticles. With decreasing MW and concentration of chitosan solution, release behavior was increased. The release of drug from TPP-chitosan microparticles decreased when cross-linking time increased. These results indicate that TPP-chitosan microparticles may become a potential delivery system to control the release of drug.

Chitin↗
PubMed2002

Preparation of alginate beads for floating drug delivery system: effects of CO(2) gas-forming agents.

Floating beads were prepared from a sodium alginate solution containing CaCO(3) or NaHCO(3) as gas-forming agents. The solution was dropped to 1% CaCl(2) solution containing 10% acetic acid for CO(2) gas and gel formation. The effects of gas-forming agents on bead size and floating properties were investigated. As gas-forming agents increased, the size and floating properties increased. Bead porosity and volume average pore size, as well as the surface and cross-sectional morphology of the beads were examined with Mercury porosimetry and Scanning Electron Microscopy. NaHCO(3) significantly increased porosity and pore diameter than CaCO(3). Incorporation of CaCO(3) into alginate solution resulted in smoother beads than those produced with NaHCO(3). Gel strength analysis indicated that bead strength decreased with increasing gas-forming agent from 9 to 4 N. Beads incorporating CaCO(3) exhibited significantly increased gel strength over control and NaHCO(3)-containing samples. Release characteristics of riboflavin as a model drug were studied in vitro. Release rate of riboflavin increased proportionally with addition of NaHCO(3). However, increasing weight ratios of CaCO(3) did not appreciably accelerate drug release. The results of these studies indicate that CaCO(3) is superior to NaHCO(3) as a gas forming agent in alginate bead preparations. The enhanced buoyancy and sustained release properties of CaCO(3)-containing beads make them an excellent candidate for floating drug dosage systems (FDDS).

Alginates↗
PubMed2002

A giant pyogenic granuloma in the nasal cavity caused by nasal packing.

Pyogenic granuloma is a benign, rapidly growing hemorrhagic lesion of unknown origin. This disorder, however, is obscure to many rhinologists, because the nose is a relatively rare location for the lesion. In the practice of otorhinolaryngology, nasal packing is a very common procedure for nasal bleeding and postoperative hemostasis. However, few pyogenic granulomas occurring from nasal packing have been reported in the literature. A 56-year-old man underwent nasal packing with vaseline gauze because of nasal bleeding. Two months later, a dark brown nasal tumor was found in his nasal cavity. He underwent endoscopic endonasal removal of the tumor. The pathology result showed a pyogenic granuloma. This is the third case recorded in the literature of a confirmed pyogenic granuloma occuring as a complication of nasal packing. This uncommon lesion should be considered in the differential diagnosis of a rapidly growing hemorrhagic lesion within the nasal fossa.

Bandages↗
PubMed2002

Leukopenia and thrombocytopenia in hemodialysis patients with hepatitis B or C virus infection and non-hemodialysis patients with hepatitis cirrhosis.

AIMS: To investigate the relation of leukopenia and thrombocytopenia in hemodialysis (HD) patients with hepatitis C virus (HCV) infection. MATERIALS AND METHODS: The study included 86 HD patients with hepatitis B surface antigen-negative and hepatitis C antibody-negative, 28 HD patients with hepatitis C antibody-positive, 22 HD patients with hepatitis B surface antigen-positive, 78 non-HD patients with hepatitis B-induced liver cirrhosis and 38 non-hemodialysis patients with hepatitis C-induced liver cirrhosis. The following parameters were checked: anti-HCV, hepatitis B surface antigen, hemoglobin, hematocrit, white blood cells, platelets, calcium, phosphate, iron, ferritin, albumin, globulin, aspartate transaminase (AST), alanine transaminase (ALT) and C-reactive protein. The history of blood transfusions, medications, erythropoietin doses and adequate dialysis (KTNV) for 6 consecutive months was also recorded from charts. RESULTS: The HD patients with positive serum anti-HCV and non-HD patients with hepatitis B- or C-induced liver cirrhosis had higher prevalences of leukopenia (39.3%, 43.6% and 50% vs. 15.1%; p < 0.001) and thrombocytopenia (67.9%, 89.7% and 81.6% vs. 34.9%: p < 0.001) than HD patients with serum anti-HCV(-)HbsAg(-). The WBC (4,432 +/- 1,394, 4,792 +/- 2,263 and 4,624 2,446 vs. 5,590 +/- 1,500/mm3; p < 0.001) and platelet counts (140 +/- 45, 80 +/- 50 and 89 +/- 65 vs. 186 +/- 62 x 10(3)/mm3; p < 0.001) of HD patients with positive serum anti-HCV and non-HD patients with hepatitis B- or C-induced cirrhosis were also lower than HD patients without anti-HCV antibody. The liver cirrhosis patients had more thrombocytopenia than the HD patients with anti-HCV(+). The WBC and platelet counts did not vary between HD patients with HbsAg(+) and HD patients with anti-HCV(-)HBsAg(-). The durations of HD, hepatitis and liver cirrhosis were not related to the leukopenia or thrombocytopenia (p > 0.05). CONCLUSIONS: HCV infection associated with leukopenia and/or thrombocytopenia in HD patients is as common as in non-HD patients with liver cirrhosis. This may be due to the direct effect of hemopoiesis rather than the hyperspleenism of liver cirrhosis patients. There is a need for further prospective investigation to ascertain the clinical significance of leukopenia and thrombocytopenia in HD patients with anti-HCV(+). The prevalence of leukopenia and thrombocytopenia was higher in HD patients with hepatitis C than in HD patients with hepatitis B and HD patient without hepatitis.

Adult↗
PubMed2002

Edema due to protein-losing enteropathy--a disorder rarely considered by nephrologists.

In the differential diagnosis, protein-losing enteropathy (PLE) is a rarely considered explanation of edema. Three such cases are reported in this article. Clinical presentations varied from severe generalized anasarca and respiratory distress to mild pitting edema on the pretibial surface. Hypoalbuminemia (< 35 g/l) was another common finding in addition to edema. The patients were carefully examined to exclude other causes of hypoalbuminemia. Two patients experienced diarrhea. Endoscopic studies (plus biopsies) for any mucosal lesion in the stomach and colon were also performed. PLE was confirmed by the positive radionuclide scanning results after infusing intravenous 99mTc human serum albumin (USA). Investigation for the etiologies showed intestinal lymphangiectasia in 1 patient, Menetrier's disease in another, and no recognizable cause in the third. The severe anasarca of the patient with intestinal lymphangiectasia didn't respond to corticosteroids and albumin supplement plus large doses of furosemide. She died of overwhelming pulmonary infection despite the use of powerful antibiotics (ceftriaxone and amikacin). We planned to treat the Menetrier's disease patient with somatostatin to decrease the exocrine activities of the intestinal tract. The patient with presumable idiopathic PLE had the least severe edema and was not treated with any medication. In addition to the above patients, another 3 patients with hypoalbuminemia and edema were also noted to have positive HSA scan results. However, 2 of these patients had systemic lupus erythromatosus and the third pulmonary tuberculosis and biopsy-proven membranous nephropathy. Treatment of their underlying diseases showed satisfactory remission of edema.

Adult↗