Fabrication of triacetylcellulose-SiO2 nanocomposites by surface modification of silica nanoparticles.

We have successfully fabricated triacetylcellulose (TAC) polymer-silica nanocomposite films having up to 40 wt % of incorporated silica nanoparticles by deliberately designing a surface ligand that has a structure similar to that of polymer repeating units and effectively modifying the surface of silica nanoparticles through chemical bonding. Cross-sectional TEM analysis reveals no significant aggregation in all TAC-silica nanocomposite films. Thermal analysis results suggested that TAC-silica nanocomposites had higher T(g) and T(c) values as compared to pure TAC, and the increase in T(g) and T(c) was affected by the silica content. The transparency of all the nanocomposite films was over 80% in the visible range, confirming the excellent compatibility of nanoparticles with TAC. In this study, we enhance the interaction between nanoparticles and polymer matrices by modifying the surface of nanoparticles with a ligand that has a structure similar to that of polymer repeating units. It is expected that this method can be applied to other polymer systems to develop useful nanocomposites.

Clinical overview of extrapulmonary small cell carcinoma.

The objective of this study was to review the natural history of extrapulmonary small cell carcinoma (EPSCC) with specific emphasis on clinical features, response to treatment and survival. The records of all patients (n=34) with EPSCC treated at Yeungnam University Medical Center and Catholic University of Daegu Medical Center between 1998 and 2005 were retrieved and reviewed. The primary sites of tumor were the esophagus and thymus in 6 patients (17.6%) each, pancreas and stomach in 5 patients each (14.7%); other sites included were the cervix, abdominal lymph nodes, abdominal wall, bladder, colon, maxillary sinus, nasal cavity, ovary, parotid gland and liver. Twenty three patients out of 34 had limited disease. The median survival of all patients was 14 months. Independent prognostic factors included stage and primary tumor location. The prognosis for the patients with extensive disease and in the gastrointestinal group was unfavorable. EPSCC is a non homogeneous disease entity. As a result of its frequent recurrence, multimodal therapy has a better outcome even in cases of limited disease. Combination chemotherapy plays a central role for treatment of extensive disease in EPSCC. Further multicenter studies are now needed to determine more details regarding disease sub-class and optimal treatment modality.

Myelodysplastic syndrome with complex karyotypic abnormality in a patient with Waldenström's macroglobulinemia after sequential treatment with chlorambucil and fludarabine.

A therapy-related myelodysplastic syndrome (t-MDS) during the course of Waldenström's macroglobulinemia (WM) has been observed in rare patients. In most of them, the condition developed after treatment with alkylating agents. We experienced a 65-year-old male patient who was diagnosed as WM. He was treated with intermittent oral chlorambucil for 12 months and three cycles of fludarabine, and complete response was achieved after fludarabine treatment. During routine outpatient follow-up, severe anemia occurred. His bone marrow aspirate showed dysplastic hemopoiesis with ringed sideroblasts and siderocytes, which is consistent with MDS (refractory anemia with ringed sideroblasts). Cytogenetic analysis showed complex chromosomal abnormalities including 5q deletion, 12p deletion and monosomy 18. When decision is made to treat WM with chlorambucil and/or fludarabine, a potential risk for t-MDS or therapy-related acute myeloid leukemia should be considered and a close hematologic monitoring is needed.

The efficacy of paclitaxel and cisplatin combination chemotherapy for the treatment of metastatic or recurrent gastric cancer: a multicenter phase II study.

BACKGROUND: Although many treatments for advanced gastric cancer have been developed, only poor treatment results have generally been obtained. We performed a prospective study on the combination chemotherapy of paclitaxel and cisplatin (PC). The primary objectives of the study were elucidating the disease response and evaluating the drug regimen's safety. METHODS: Patients with metastatic or recurrent gastric cancer received intravenous paclitaxel 175 mg/m2, and cisplatin 70 mg/m2 on day 1. This cycle was repeated every 3 weeks. RESULTS: From January 2000 to March 2004, 37 patients from 3 different hospitals were enrolled in this study. A total of 135 treatment cycles (median: 3 cycles) were administered. The responses were evaluable in 34 patients; 24 patients received this regimen as their first-line treatment for metastatic cancer and the other patients received it as their second-line treatment for recurrent cancer. The objective response rate (RR) was 26.5% (95% CI: 11.7-41.3) with two complete responses, and stable disease was observed in 41.1% of the patients. Importantly, an RR of 33.3% (95% CI: 0.6-66.0) was achieved for the eight patients who received this regimen as a first-line treatment. The median follow up duration was 14 months for all the patients, and the median time to progression was 6 months (95% CI: 1.9-10.2). The overall survival time was 8.9 months (95% CI: 7.0-11.0) with a 1-year survival rate of 18.7% (95% CI: 5.6-31.8). The most common toxicity was neutropenia. CONCLUSION: PC exhibited promising activity against gastric cancer for the previously untreated patients as a first-line treatment with an acceptable toxicity profile.

New catalyst design for polymerization of norbornene esters by reducing intramolecular interaction.

We have used density functional theory to study palladium-based catalysts commonly used for the polymerization of norbornene derivatives with an ester group. Exo-exo, exo-endo, and endo-endo isomers of catalyst complexes were investigated; the endo-endo isomer was the most stable and inactive due to an intramolecular interaction between Pd and O of the carbonyl group. Phosphine groups are effective in minimizing the Pd-O interaction in the endo-endo isomer and P(C6H11)3 was found to be the most efficient reagent. The intramolecular Pd-O interactions were estimated using model complexes, and it was demonstrated that they play a crucial role in stabilizing the endo-endo isomer.

Direct Lanthanide-Transition Metal Interactions: Synthesis of (NH(3))(2)YbFe(CO)(4) and Crystal Structures of {[(CH(3)CN)(3)YbFe(CO)(4)](2).CH(3)CN}(infinity) and [(CH(3)CN)(3)YbFe(CO)(4)](infinity).

The heterometallic complex (NH(3))(2)YbFe(CO)(4) was prepared from the reduction of Fe(3)(CO)(12) by Yb in liquid ammonia. Ammonia was displaced from (NH(3))(2)YbFe(CO)(4) by acetonitrile in acetonitrile solution, and the crystalline compounds {[(CH(3)CN)(3)YbFe(CO)(4))](2).CH(3)CN}(infinity) and [(CH(3)CN)(3)YbFe(CO)(4)](infinity) were obtained. An earlier X-ray study of {[(CH(3)CN)(3)YbFe(CO)(4)](2).CH(3)CN}(infinity) showed that it is a ladder polymer with direct Yb-Fe bonds. In the present study, an X-ray crystal structure analysis also showed that [(CH(3)CN)(3)YbFe(CO)(4)](infinity) is a sheetlike array with direct Yb-Fe bonds. Crystal data for {[(CH(3)CN)(3)YbFe(CO)(4)](2).CH(3)CN}(infinity): monoclinic space group P2(1)/c, a = 21.515(8) Å, b = 7.838(2) Å, c = 19.866(6) Å, beta = 105.47(2) degrees, Z = 4. Crystal data for [(CH(3)CN)(3)YbFe(CO)(4)](infinity): monoclinic space group P2(1)/n, a = 8.364(3) Å, b = 9.605(5) Å, c = 17.240(6) Å, beta = 92.22(3) degrees, Z = 4. Electrical conductivity measurements in acetonitrile show that these acetonitrile complexes are partially dissociated into ionic species. IR and NMR spectra of the solutions reveal the presence of [HFe(CO)(4)](-). However, upon recrystallization, the acetonitrile complexes show no evidence for the presence of [HFe(CO)(4)](-) on the basis of their IR spectra. The solid state MAS (2)H NMR spectra of deuterated acetonitrile complexes give no evidence for [(2)HFe(CO)(4)](-). It appears that rupture of the Yb-Fe bond could occur in solution to generate the ion pair [L(n)Yb](2+)[Fe(CO)(4)](2-), but then the highly basic [Fe(CO)(4)](2-) anion could abstract a proton from a coordinated acetonitrile ligand to form [HFe(CO)(4)](-). However, upon crystallization, the proton could be transferred back to the ligand, which results in the neutral polymeric species.