Template synthesis of asymmetrically mesostructured platinum networks.
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Journal Article↗
Biomedical subjects
H J Shin
Publications and source records attributed to H J Shin.
Soliton scattering from a finite cnoidal wave train in a fiber.
We analyze the scattering of a soliton from a cnoidal wave train in a fiber theoretically as well as numerically. Solitons recover their original shapes and velocities after collisions, while shapes of cnoidal waves are nearly preserved during collisions. The effect of collisions is described by the change of velocities of solitons, and the theoretical predictions are in good agreement with numerical results.
Journal Article↗
Clinical application of continent anal plug in bedridden patients with intractable diarrhea.
PURPOSE: Some patients bedridden from various causes such as stroke or spinal cord injury experience poor control of bowel movement. This causes fecal leakage and diarrhea, increases the risk of perianal excoriation and bed sores, and is a burden on caregivers. To evaluate the efficacy of fecal evacuation and the prevention and treatment of skin complications in intractable diarrhea patients using a new device. METHODS: A continent anal plug (US Patent No. 5 569 216) comprises an inner balloon surrounded by an outer balloon, both of which are mounted on a silicone tube containing a pair of air passages and an enema fluid inlet. The tube is secured in place in the rectum by the inflatable outer balloon and is designed to drain fecal matter through a thin collapsible hose situated in the anal canal. Thirty-two patients (21 male; median age 61 (range, 28-76) years) were evaluated after fully informed consent. Median duration was 12 (range, 3-37) days. RESULTS: The continent anal plug evacuated efficiently in those patients with loose or watery stools who only required irrigation once daily or not at all. Skin excoriations improved in three to seven days. Minimal leakage was seen around the anus. There was no anorectal mucosal injury noted over 37 days. CONCLUSIONS: The continent anal plug is an efficient method of treating patients with loss of bowel control and incontinence because it enables controlled fecal evacuation and helps reduce skin complications without causing anorectal mucosal injury.
Adult↗
Indomethacin-loaded methoxy poly(ethylene glycol)/ poly(epsilon-caprolactone) diblock copolymeric nanosphere: pharmacokinetic characteristics of indomethacin in the normal Sprague-Dawley rats.
We prepared the drug-loaded polymeric nanospheres composed of the methoxy poly(ethylene glycol) (MePEG) and poly(epsilon-caprolactone) (PCL) that showed a narrow size distribution and average diameter of less than 200 nm. We could obtain the nanosphere having a relatively high drug-loading efficiency of about 42% when the feed weight ratio of indomethacin (IMC) to polymer was 1:1. To investigate the IMC pharmacokinetics in the IMC-loaded MePEG/PCL nanosphere (DMEP70) using the rats as animal model, we analyzed the IMC concentration in plasma with HPLC after i.v. bolus administered at a dose of 10 mg/kg in free IMC (control) and IMC-loaded MePEG/PCL nanosphere (DMEP70) groups via tail vein. Pharmacokinetics parameters (mean +/- s.d.) such as the mean residence time (MRT, h), the steady-state volume of distribution (Vdss, l), the terminal half-time (t 1/2, h) and the plasma clearance (CL, l/h) of IMC in each groups (control vs. DMEP70) were determined; MRT (16.97 +/- 4.83 vs. 28.69 +/- 11.28, p < 0.01); Vdss (14.26 +/- 4.86 vs. 20.37 +/- 12.04, p < 0.05); t 1/2 (15.12 +/- 4.77 vs. 23.1 +/- 8.24, p < 0.01); CL (0.84 +/- 0.27 vs. 0.71 +/- 0.41). From these results, we could concluded that MEP70 has a significant potential for sustained release and the enhancement of circulation time of loaded drug by prolonging terminal half-life, increasing MRT and Vdss of IMC. Therefore, The MePEG/PCL block copolymeric nanosphere system is being considered as promising biodegradable and biocompatible drug carrier vehicles for parentral use and may be useful as sustained release injectable delivery systems for hydrophobic drugs.
Animals↗
Once-a-day oral dosing regimen of cyclosporin A: combined therapy of cyclosporin A premicroemulsion concentrates and enteric coated solid-state premicroemulsion concentrates.
PURPOSE: To develop once-a-day oral dosing regimen that provides the blood levels of cyclosporin A (CsA) in the therapeutic ranges over 24 hours. METHODS: CsA premicroemulsion concentrates (preME) were formulated from phase diagrams. Enteric-coated solid-state premicroemulsion concentrates (sME) were prepared by coating preME with enteric-coating matrials and solidifying them. CsA was measured using high-performance liquid chromatography or radioimmunoassay. RESULTS: PreME consisted of CsA, oil, and mixture of surfactants and a cosurfactant. PreME spontaneously formed microemulsions in aqueous medium and showed oral absorption profiles similar to Sandimmune Neoral in dogs. Dispersion of sME in aqueous medium also formed microemulsions. Release rates of CsA from sME depended on pH and the type of enteric-coating materials and highly correlated with the extent of oral absorption. The co-administration of preME and sME (200 mg CsA) showed the maximum blood level of CsA not significantly different from that of preME (100 mg CsA) and the concentration of CsA close to the minimum therapeutic level at 24 hours. CONCLUSIONS: The combined treatment of preME and sME provided controlled oral absorption of CsA over a 24-hour period. Such once-a-day dosing regimens will lead to increased patient compliance and reduced episodes of organ rejection after transplantation.
Administration, Oral↗
Surgical tactics and outcome of treatment in jugular foramen schwannomas.
Seven patients with schwannomas of the jugular foramen were included our study in Samsung Medical Center between 1995 and 1999. Patients with neurofibromatosis were excluded. The records of the seven patients (six surgical case and one nonsurgical case) were retrospectively reviewed. There were six women and one man (mean age, 47 years) with a symptom duration ranging from 3 months to 14 years (mean, 47 months). The predominant symptoms were hearing difficulty, hemifacial spasm and hoarseness. Preoperative audiologic evaluation, computerised tomography (CT), magnetic resonance (MR) imaging, and angiography were performed in most patients. We classified tumours into four types using Kaye and Pellet classification on the basis of radiological and surgical findings. The tumours were: Type A (at cerebellopontine angle) in one; Type B (foraminal) in two; Type C (extracranial and/or foraminal) in two; and Type D (intra- and extracranial) in two cases. We used various surgical approaches such as retrosigmoid suboccipital craniectomy for Type A tumours, infratemporal fossa type A approach (ITFA) for Type C tumours, petro-occipital transsigmoid approach or modified transcochear approach for Type D tumours and ITFA with partial labyrinthectomy for Type B. In the selection of surgical approaches, we took consideration of tumour extension, tumour size, and preoperative hearing function. Facial nerve transposition was not used only in one case of ITFA because of small tumour size (1.5cm). Gross total removal was achieved in five cases, and subtotal removal in one case (Type D tumour) with a single-stage operation. Stereotactic radiosurgery was performed on residual mass in the subtotally removed case. Follow-up period ranged from 13 to 49 months (mean, 27.5 months). There was neither postoperative mortality nor recurrence on follow-up MR imaging. There were two cases of temporary facial nerve palsy and one aggravation of pre-existing low cranial palsy. Two case of sustained vocal cord palsy underwent thyroplasty, but there was no aspiration pneumonia. Persistent cerebrospinal fluid collection was improved with lumboperitoneal shunt. The surgical approaches of each case should be tailored according to their shape and the clinical manifestation. We obtain acceptable outcomes from one-stage operation.
Accessory Nerve↗
Nitric oxide is involved in the immunomodulating activities of acidic polysaccharide from Panax ginseng.
The effects of an acidic polysaccharide isolated from the ethanol-insoluble and water-soluble fraction of Panax ginseng C. A. Meyer on immunomodulating activities were investigated. A high output nitric oxide synthase (iNOS) was shown in female BALB/c mice administered intraperitoneally with the acidic polysaccharide from ginseng. Newly synthesized iNOS protein was also observed in peritoneal macrophages cultured with interferon-gamma and the acidic polysaccharide. Spleen cells from acidic polysaccharide-treated mice did not proliferate in response to concanavalin A, but restored the responsiveness by the cotreatment of NG-monomethyl-L-arginine (NMMA) with concanavalin A. The treatment of mice with aminoguanidine, a specific iNOS inhibitor, alleviated the acidic polysaccharide-induced suppression of antibody response to sheep red blood cells. Present results suggest that the immunomodulating activities of the acidic polysaccharide were mediated by the production of nitric oxide.
Adjuvants, Immunologic↗
Cytopathic changes in rat microglial cells induced by pathogenic Acanthamoeba culbertsoni: morphology and cytokine release.
To determine whether pathogenic Acanthamoeba culbertsoni trophozoites and lysate can induce cytopathic changes in primary-culture microglial cells, morphological changes were observed by transmission electron microscopy (TEM). In addition, the secretion of two kinds of cytokines, tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta), from microglial cells was observed. Trophozoites of pathogenic A. culbertsoni made contact with microglial cells and produced digipodia. TEM revealed that microglial cells cocultured with amoebic trophozoites underwent a necrotic process, accompanied by lysis of the cell membrane. TEM of microglial cells cocultured with amoebic lysate showed that the membranes of the small cytoplasmic vacuoles as well as the cell membrane were lysed. The amounts of TNF-alpha secreted from microglial cells cocultured with A. culbertsoni trophozoites or lysate increased at 6 h of incubation. The amounts of IL-1beta secreted from microglial cells cocultured with A. culbertsoni trophozoites at 6 h of incubation was similar to those secreted from the control group, but the amounts decreased during cultivation with A. culbertsoni lysate. These results suggest that pathogenic A. culbertsoni induces the cytopathic effects in primary-culture rat microglial cells, with the effects characterized by necrosis of microglial cells and changes in levels of secretion of TNF-alpha and IL-1beta from microglial cells.
Acanthamoeba↗
Susceptibility of ducks to avian pneumovirus of turkey origin.
OBJECTIVE: To determine the susceptibility of ducks to avian pneumovirus (APV) of turkey origin. ANIMALS: 30 Pekin ducks that were 2 weeks old. PROCEDURE: Ducks were assigned to 3 groups (10 ducks/group). Ducks of groups 1 and 2 were inoculated (day 0) with 200 microl of cell-culture fluid containing APV of turkey origin (10(5.5) median tissue-culture infective dose/ml) by the oculonasal (group 1) or oral (group 2) route. Ducks of group 3 served as noninoculated control birds. Two ducks from each group were euthanatized 3, 6, 9, 15, and 21 days after inoculation. Blood samples, tissue samples from the lungs, trachea, nasal turbinates, duodenum, diverticulum vitellinum (Meckel's diverticulum), and cecum, and swab specimens from the choana, cloaca, and trachea were obtained from all birds during necropsy and examined for APV by use of reverse transcriptase-polymerase chain reaction (RT-PCR), virus isolation, and histologic examination. Blood samples also were examined for APV antibodies, using an ELISA. RESULTS: Tissue samples obtained up to 21 days after inoculation had positive results when tested by use of RT-PCR. Virus was isolated from nasal turbinates of birds inoculated via the oculonasal route. Serum samples obtained 15 and 21 days after inoculation had positive results when tested for APV-specific antibody. Clinical signs of disease were not observed in ducks inoculated with APV of turkey origin. CONCLUSIONS AND CLINICAL RELEVANCE: Ducks inoculated with APV of turkey origin may not develop clinical signs of disease, but they are suspected to play a role as nonclinical carriers of APV.
Animals↗
Increased burst firing in substantia nigra pars reticulata neurons and enhanced response to selective D2 agonist in hemiparkinsonian rats after repeated administration of apomorphine.
Intermittent administrations of dopaminergic agents in hemiparkinsonian rat enhances the behavioral response to subsequent administration of the drugs. This phenomenon is known as "priming" and thought as comparable to drug-induced dyskinesia in patients with Parkinson's disease. We investigated the behavioral and electrophysiological changes in 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rats after repeated administrations of apomorphine. Administration of apomorphine (0.32 mg/kg, intraperitoneal, i.p.) twice daily for 6 days enhanced the rotation induced by apomorphine from 341 turns/hour at the beginning to 755 turns/hr at the end. At the same time, the response to selective D2 agonist quinpirole (0.26 mg/kg, i.p.) was also enhanced from 203 to 555 turns/hr. Extracellular single unit recording revealed no significant difference in the basal firing rates of substantia nigra pars reticulata (SNr) neurons between the ipsilateral and contralateral side of the 6-OHDA lesion regardless of the repeated administrations of apomorphine. In SNr of the lesion side, the units with burst firing pattern were found more frequently after repeated administrations of apomorphine and the suppressive effect of quinpirole on the firing rate was enhanced. These findings suggest that the increased percentage of the burst units is the important electrophysiological change in the development of enhanced response to selective D2 agonist.
Animals↗
Diphyllobothrium latum infection after eating domestic salmon flesh.
Diphyllobothrium latum infection in human is not common in Korea and only thirty seven cases have been reported since 1921. We report two cases of fish tapeworm infection after ingestion of raw cherry salmon (Oncorhynchus masou) caught in the domestic river. Among four family members who ate together raw salmon flesh six months ago, just two, mother and daughter, were infected. It is our expectation that the salmon associated tapeworm infections would be enlisted as one of the major parasitic problems with the growing consumption of salmon in Korea.
Adult↗
Squamous cell carcinoma of the cornea.
In this paper, a case of corneal squamous cell carcinoma is reported. Invasive squamous cell carcinoma of the cornea is a rare disorder and has not been previously described in the Korean literature. In this case, the invasive squamous cell carcinoma of the cornea was treated by complete excision and cryotherapy. No evidence of metastasis or recurrence has been found since the procedure. Complete excision and adjunctive cryotherapy has become the treatment of choice because of the higher recurrence rate following a simple excision.
Aged↗
Subcutaneous bronchogenic cyst: unusual unltrasonographic findings.
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Bronchogenic Cyst↗
Epidermal growth factor receptor-targeted therapy with C225 and cisplatin in patients with head and neck cancer.
C225, a human-mouse chimerized monoclonal antibody directed against the epidermal growth factor receptor (EGFr), has a synergistic effect with cisplatin in xenograft models. To determine the tumor EGFr saturation dose with C225 and the fate of infused C225, we conducted a Phase Ib study with C225 in combination with cisplatin in patients with recurrent squamous cell carcinoma of the head and neck. Using tumor samples, we assessed tumor EGFr saturation by antibody using immunohistochemistry studies, the EGFr tyrosine kinase assay, and detection of the EGFr/C225 complex formation by immunoblot. Potential candidates were screened for EGFr expression in their tumors, and 12 patients who had high levels of EGFr expression and tumors easily accessible for repeated biopsies (pretherapy, 24 h after first C225 infusion, 24 h before third C225 infusion) were entered at three different dose levels of C225 with a fixed dose of cisplatin. The median value of tumor EGFr saturation increased to 95% at the higher dose levels. EGFr tyrosine kinase activity was significantly reduced after C225 infusion, and EGFr/C225 complexes were also detected at higher doses of C225. The loading dose of C225 at 400 mg/m(2) with a maintenance dose at 250 mg/m(2) achieved a high percentage of saturation of EGFr in tumor tissue, and these doses were recommended for Phases II or III clinical trials. Six (67%) of nine evaluable patients achieved major responses, including two (22%) complete responses. Mild to moderate degrees of allergic reaction and folliculitis-like skin reactions were demonstrated. We conclude that infused C225 binds and significantly saturates tumor EGFr, which may render a high degree of antitumor activity, and provides a novel mechanism for targeting cancer therapy for patients who have EGFr expression in their tumors.
Adult↗
Distinction of phyllodes tumor from fibroadenoma: a reappraisal of an old problem.
BACKGROUND: Using fine-needle aspiration (FNA) smears, it is difficult to distinguish low grade phyllodes tumor (PT) from fibroadenoma (FA) due to overlapping cytologic features between the two lesions. The authors retrospectively studied 45 histologically proven fibroepithelial breast tumors of which 33 were FA and 12 were PT (1 malignant, 8 borderline, and 3 benign) to define cytologic features that can help in the accurate categorization of these lesions by using FNA samples. METHODS: The cytologic features analyzed included: 1) epithelial component for number (<5 or >5), architecture, apocrine metaplasia, squamous metaplasia, nuclear pleomorphism, and mitosis; 2) stromal fragments for number (<5 or >5), cellularity (on a scale of 1+ to 3+), borders, cell characteristics, nuclear pleomorphism, and mitosis; 3) individual dispersed stromal cells in the background for cellularity (on a scale of 1+ to 3+), and cellular shape (short/round/oval or long spindle) based on whether they were smaller or larger than 2 times the size of a small round lymphocyte. RESULTS: The mean age of patients with FA was 34 years and of those with PT 44 years. The average size of FA was 2.0 cm, and the average size of PT was 4.0 cm. The characteristics of the epithelial fragments of PT and FA were not significantly different. Stromal fragments were noted in 60% of FA and 83% of PT samples examined. Fifty-six percent of PT and 30% of FA exhibited hypercellular stromal fragments (3+ cellularity), and the difference was not statistically significant. Large club-shaped hypercellular stromal fragments were present only in FA (in 21% of the samples). There was no difference in the overall cellularity of the background stromal nuclei in the two types of lesions. Long spindle nuclei averaging greater than 30% of the dispersed stromal cell population in the background were found only in cases of PT (in 57% of the samples; P < 0.001). Short/round/oval nuclei characterized most FAs. Long spindle nuclei constituting 10-30% of the dispersed stromal cells, however, occurred in both PT and FA to the extent of 43% and 21%, respectively. CONCLUSIONS: Hypercellular stromal fragments occur not only in PT, but also in FA, and hence they cannot be used as the sole criterion for making a diagnosis of PT on FNA. The proportion of individual long spindle nuclei (>30%) amid the dispersed stromal cells in the background is the most reliable discriminator between the two lesions. Lesions in which long spindle nuclei constitute between 10% and 30% may represent either PT or FA, and therefore such lesions should be categorized as indeterminate on FNA.
Adult↗
Fine-needle aspiration biopsy of granulocytic sarcoma: a clinicopathologic study of 27 cases.
BACKGROUND: Because of morphologic similarities, the differential diagnosis of granulocytic sarcoma (GS) in fine-needle aspiration (FNA) specimens includes non-Hodgkin or Hodgkin lymphoma, extramedullary hematopoiesis, poorly differentiated carcinoma, and infection. METHODS: Twenty-six FNAs and 1 pleural effusion fluid specimen of GS obtained from 23 patients were reviewed for cytomorphologic features and clinical characteristics. The cases were categorized as blastic, immature, or mature GS based on the population of the cells present on the smears. RESULTS: The patients included 18 men and 5 women (mean age, 54 years). Aspiration sites included subcutaneous or soft tissue (15 cases), lymph nodes (5 cases), bones (3 cases), testis (1 case), ileum (1 case), and liver (1 case). One sample of pleural effusion fluid also was included. Review of the patients' clinical history revealed that GS was secondary to chronic myelogenous leukemia (CML) in 17 patients, was secondary to chronic myelomonocytic leukemia (CMML) in 2 patients, and was secondary to acute myelogenous leukemia in 2 patients. GS preceded the manifestation of CML in one patient and of CMML in another patient. Based on the proportions of cells, morphologic classification was attempted and revealed blastic GS in 8 aspirates and 1 pleural effusion fluid specimen, immature GS in 13 aspirates, and mature GS in 5 aspirates. Twelve of 22 specimens from extranodal sites (55%) demonstrated lymphoglandular bodies in the background. Five aspirates showed rare eosinophilic myelocytes. Auer rods were not identified in any of the aspirates. Immunophenotypic and histochemical studies confirmed myeloid and/or myelomonocytic differentiation. CONCLUSIONS: GS especially can be confused with non-Hodgkin lymphoma because of morphologic similarities of the blasts to large cell lymphoma, the presence of lymphoglandular bodies, and the rarity of Auer rods and eosinophilic myelocytes. In conjunction with careful cytomorphologic evaluation, knowledge of the patient's clinical history and use of appropriate immunophenotypic studies should lead to a correct diagnosis.
Adult↗
Direct imaging of the pores and cages of three-dimensional mesoporous materials.
Mesostructured composite materials, with features ranging from 20 to 500 A in size, are obtained by the kinetically controlled competitive assembly of organic and inorganic species into nanostructured domains. Short-range order is limited, and long-range order is determined by weak forces such as van der Waals or hydrogen-bonding. Three-dimensional mesoporous materials obtained by removing the organic phase are of particular interest for applications such as catalysis and chemical sensing or separation, for which structural features such as cavity shape, connectivity and ordered bimodal porosity are critical. But atomic-scale structural characterization by the usual diffraction techniques is challenging for these partially ordered materials because of the difficulty in obtaining large (> 10 microm) single crystals, and because large repeat spacings cause diffraction intensities to fall off rapidly with scattering angle so that only limited small-angle data are available. Here we present a general approach for the direct determination of three-dimensional mesoporous structures by electron microscopy. The structure solutions are obtained uniquely without pre-assumed models or parametrization. We report high-resolution details of cage and pore structures of periodically ordered mesoporous materials, which reveal a highly ordered dual micro- and mesoscale pore structure.
Journal Article↗
Eosin interaction of alpha-synuclein leading to protein self-oligomerization.
Among various dyes including congo red, thioflavin S, thioflavin T, eosin, rhodamine 6G, and phenol red, the eosin was the only dye that induced self-oligomerization of alpha-synuclein in the presence of a chemical coupling reagent of N-(ethoxycarbonyl)-2-ethoxy-1, 2-dihydroquinoline. To analyze chemical nature of the eosin interaction with alpha-synuclein, the phenomenon of self-oligomerization was further examined with eosin congeners such as ethyl eosin, eosin B, phloxine B, erythrosin B, and rose bengal. The followings are the conclusions we have reached. First of all, intactness of the benzoate moiety of eosin and the negative charge on the carboxylic group of the dye are important factors leading to the specific interaction with alpha-synuclein. Secondly, the localized negative charge on the xanthene moiety of eosin is another critical factor for the interaction. As far as substituting halides are concerned, bromides and iodides on the xanthene moiety of the dyes do not make any difference on the alpha-synuclein interaction because both eosin and erythrosin B have induced the common phenomenon of self-oligomerization. The binding curve between eosin and alpha-synuclein was sigmoidal as the dye concentrations were increased. A double reciprocal plot of the saturation curve showed that the maximum number of eosin binding sites on alpha-synuclein was 1.85 with a dissociation constant of 390 microM. The dye binding to the protein appeared to occur via a positive cooperativity. The eosin binding site(s) was suggested to be located predominantly on the NAC region and partly related to the acidic C-terminus of alpha-synuclein. It has been, therefore, expected that this information might be useful to develop alpha-synuclein interactive molecules, which could provide eventual preventive or possible therapeutic means against various alpha-synuclein related disorders including Parkinson's disease.
Dose-Response Relationship, Drug↗