Gas‐Phase Assisted Surface Polymerization of Vinyl Monomers with Fe‐Based Initiating Systems

Summary: Gas‐phase assisted surface polymerization (GASP) of methyl methacrylate (MMA) and styrene (St) was investigated with Fe‐based radical initiating systems, FeCl₂/2,2′‐bipyridine (Bpy)/methyl α‐bromophenylacetate (MBPA), etc. GASP with these initiating systems proceeded to produce corresponding polymers on substrate surfaces. The resulting PMMA had very high PDI values, suggesting an uncontrolled reaction. In an attempt to control the GASP, polymerization with a simple initiating system, Fe(0)/MBPA, was examined on Fe(0)‐metal surfaces, resulting in significant polymerization activity to produce high‐molecular‐weight PMMA. The results of time‐course tests on GASP of MMA and St suggested that a change had taken place to produce physically controlled propagation sites on the Fe(0) powder surfaces.

GASP schemes with a simple initiating system Fe(0)/MBPA.     

Mutations of the BAK gene are infrequent in advanced gastric adenocarcinomas in Koreans

The bcl-2 homologue antagonist/killer (BAK) is a potently apoptosis-inducing gene and plays an important role in modulating apoptosis in epithelial cells. We have analyzed the mutation of the entire coding region of BAK gene in 107 Korean advanced gastric adenocarcinomas by polymerase chain reaction-single strand conformation polymorphism and sequencing. Homozygous deletions were not found in these samples. Only three cases of 107 gastric adenocarcinomas (2.8%) exhibited the BAK mutations. Two of them exhibited missense mutations and the remaining one had a silent mutation. All of these mutations were exclusively detected in exon 2. Mutations in the BAK gene were observed only in advanced gastric adenocarcinomas with extensive metastases of regional lymph nodes. The data presented here suggest that the mutations of BAK gene rarely occurred in advanced gastric adenocarcinomas.     

Vulnerable atherosclerotic plaque: clinical implications

Coronary Artery Disease (CAD) remains globally the leading cause of death and long-term morbidity. Among the many manifestations of CAD, acute coronary syndrome (ACS), ranging from unstable angina to acute myocardial infarction, is the most catastrophic event due to our inability to predict its occurrence. Despite improved treatments of CAD, ACS results in sudden death or permanent disability in a substantial percentage of patients. If we could predict the timing of ACS or better yet prevent its occurrence, we could alter the otherwise unfavorable course of CAD. Several studies have convincingly demonstrated that majority of all ACS develops from previously mild to moderate stenoses. Thus, based on these and autopsy studies, sudden disruption or rupture of the non-obstructive "vulnerable" atherosclerotic lesion is currently considered the cause of ACS. Recent clinical studies have substantiated earlier autopsy observations that plaque vulnerability is a systemic process, involving multiple locations concurrently. Although the exact inciting factors of the vulnerable plaque rupture are unknown, inflammation is accepted to be a pivotal event. The possibility of stabilizing the vulnerable plaques has strongly been supported by the lipid lowering trials, in which dramatic reduction of the acute coronary events was noted despite subtle improvements in luminal diameter. Furthermore, antiplatelet therapies have become an important preventative therapy due to the essential role of platelets in the aftermath of plaque rupture. Finally, various imaging modalities to diagnose the plaque vulnerability could help prevent the acute coronary events in the future.     

Intraoperative complications of thoracoscopic surgery for mediastinal tumors

We report intraoperative complications of thoracoscopic surgery for mediastinal tumors. Forty cases of mediastinal tumor were undergone thoracoscopic surgery at the hospital from 1999 to 2002. The patient's ages ranged from 18 to 74 years old with a mean of 47.7. Location of these tumors were anteriormediastinal in 20 cases, middlemediastinal in 6 cases, posteriormediastinal in 11 cases, and superiormediastinal in 3 cases. Intraoperative complications were rupture of the cyst in 9 cases, bleeding over 150 ml in 5 cases, injury of lung caused by adhesiolysis in 5 cases, and injury of nerve in 3 cases. The mean operation time was 103.8 minutes. Postoperative hospital stay ranged from 2 to 22 days with a mean of 5.9 days. All are alive with no recurrences or postoperative complications.     

Mucosa-associated lymphoid tissue lymphoma of the thymus resected using combined thoracoscopic and transcervical approaches

Mucosa-associated lymphoid tissue (MALT) lymphoma is a low-grade variant of B cell lymphoma that arises in extranodal tissue of the gastrointestinal tract, lung, salivary gland, thyroid, or other organ derived from the foregut. However, MALT lymphoma in the thymus is extremely rare. We report a case of thymic MALT lymphoma, extending to the neck, resected using combined thoracoscopic and transcervical approaches. To the best of our knowledge, thoracoscopic management of MALT lymphoma in the thymus has not previous been reported.     

Inhibition of erythropoietin activity by cyanate

OBJECTIVE: Increased urea concentration is a measure of advanced renal failure and the adequacy of renal replacement therapy in end-stage renal disease (ESRD). Altered biologic activity due to changes in protein structure occurs when cyanate, formed spontaneously from urea, reacts with proteins. Carbamylation results in impaired erythropoietin (EPO) activity when high concentrations of cyanate react with EPO. In this study, the activity of carbamylated EPO (C-EPO), formed at a cyanate concentration which may occur in vivo, was studied in Sprague-Dawley rats. MATERIAL AND METHODS: The extent of carbamylation, causing loss of free amino groups, was monitored using trinitrobenzenesulfonic acid. Erythrocyte, hemoglobin, hematocrit and leukocyte levels were measured after either EPO, incubated EPO, C-EPO, physiologic saline or cyanate (1.5 microM; 0.2 ml) were injected subcutaneous twice weekly for 3 weeks in rats. RESULTS: In vitro carbamylation of EPO was time- and concentration-dependent. C-EPO concentration increased as the duration of exposure to cyanate increased from 6 to 72 h, or as cyanate concentration increased from 15 nM to 1.5 microM. Injections of EPO caused significant increases in vivo in all erythropoietic measures. In contrast, injections of C-EPO, physiologic saline or 1.5 microM cyanate caused no change from baseline. CONCLUSIONS: These results demonstrated diminished biologic activity in healthy rats by C-EPO formed in vitro at cyanate concentrations that may be found in vivo. C-EPO and high urea-derived cyanate levels may contribute to suboptimal erythropoietic responses to EPO therapy for chronic renal failure and ESRD, and may provide another measurement indicating inadequate dialysis.     

Result of photodynamic therapy for idiopathic subfoveal choroidal neovascularization

PURPOSE: To investigate the factors that affect final vision following photodynamic therapy (PDT) for idiopathic subfoveal choroidal neovascularization (CNV). METHODS: A retrospective review of 16 patients whose eyes were diagnosed as idiopathic subfoveal CNV and were followed up for a minimum of 9 months. Statistical analysis was performed to investigate relationships between sex, age, size of the lesion, and initial vision compared to final vision. RESULTS: In the PDT group (10 eyes), the mean age of the patients was 34 years, mean size of the lesion was 1300 microm, mean initial vision was 20/60, and 7 of the 10 patients (70%) showed more than a two-line improvement in vision. Factors affecting final vision were sex (p=0.049), initial vision (p=0.0455), and size of the lesion (p=0.006). In the observation group (6 eyes), the mean age of the patients was 39 years, mean size of the lesion was 575 microm, mean initial vision was 20/32, and 5 of the 6 patients (83%) showed more than a two-line improvement in vision. CONCLUSIONS: The prognosis of idiopathic CNV was favorable as was reported in other studies. In the PDT group, statistically significant factors affecting final vision were initial vision, size of the lesion, and sex. However, since the number of patients sampled was insufficient and the average size of the lesions in the female patients was smaller, the size of the lesion seems to be the most important factor.