Scheme I 4 concomitantly, 2-methylene ketone 4g was formed (monitored by NMR). After 4 h, dehydrostannation was complete, and the precipitate was filtered off. Aqueous workup of the filtrate (pentane/aqueous NH4C1) followed by evaporation of the solvents and bulb-to-bulb distillation afforded 2-methylenecycloheptanone (4g) in 80% yield. Similarly, essentially quantitative conversion of 3 to 4 (eq 1) was observed in the reaction of 3 with Me2SO-d6/CDCl3 3 4 at 60 °C (by NMR) except for 3f which did not bear hydrogen ß to the stannyl group.9 The results are shown in Table I. The dehydrostannation of 3d,e,g,h proceeded with shorter reaction time than 3a-c. It seems that for dehydrostannation to occur, the intramolecular coordination of the carbonyl oxygen to the Sn atom (as indicated by IR) may play a key role. In fact, dehydrostannation did not take place with simple n-BuSnCl3 even under more forcing conditions (60 °C, 1 day). One plausible explanation for the present reaction is shown in Scheme I. The initial role of Me2SO may be the one as a base toward /3-hydrogen10 which may be sufficiently acidic due to the inductive effect of the adjacent carbonyl coordinated to the Sn. Thus, the deprotonation from 5 and subsequent destannylation via 6 would occur to lead to 4 and HSnCl3(Me2SO)" complex.11,12 Interestingly, the reaction of siloxycyclopropane 7 with SnCl4 in CH2C12 proceeded similarly and afforded ß-tríchlorostannyl aldehyde 8 (semisolid, vc=0 1680 cm-1). The (9) As the preparative method of /3-stannyl ketones 3, hydrostannation of ,/8-unsaturated ketones with HSnClg (in situ generated under acidic conditions: HC1 and SnCl2) has been known. The observed dehydrostannation promoted by Me2SO formally corresponds to its reverse reaction. See:
Abstract:Background. The frequency of tumors in the upper one-third of the stomach has been increasing. The standard operation for proximal gastric cancer has been total or proximal gastrectomy. The aim of this study was to present the pathologic and surgical results of 30 patients with early-stage proximal gastric cancer managed by proximal gastrectomy. Methods. A consecutive series of 30 patients who underwent proximal gastrectomy for early-stage proximal gastric cancer was studied. Sixteen patients underwent jejunal interposition, while 14 underwent gastric tube reconstruction, which consisted of a direct anastomosis between the esophagus and the remnant of the tube-like stomach. Results. Twenty patients (67%) had no abdominal symptoms and the lesions were detected by screening gastric fiberscopy. The tumors were mostly located along the lesser curvature (73%), were grossly depressed type (IIc) (70%), and histologically well differentiated type (63%). The depth of wall invasion was the mucosa in 12 patients, submucosa in 15, and muscularis propria in 3; lymph node metastasis was absent in 28 patients (93%). When compared with patients with jejunal interposition, patients with gastric tube reconstruction had a shorter operation time (327 vs 165 min), less blood loss (508 vs 151 g), and shorter hospital stay after operation (31 vs 17 days). Endoscopy and 24-h pH monitoring showed no evidence of reflux esophagitis, except in 1 patient with gastric tube reconstruction, and no patient died of recurrence. Conclusions. Early-stage proximal gastric cancer can be successfully treated by proximal gastrectomy. Since gastric tube reconstruction is a simple, easy, and safe procedure, proximal gastrectomy followed by gastric tube reconstruction is recommended for patients with early-stage proximal gastric cancer.
Offprint requests to: Y. Adachi
Amphiphilic hyaluronic acid (HA) derivatives bearing hydrophobic indocyanine green dye derivatives and hydrophilic poly(ethylene glycol) were synthesized through the use of condensation and copper-catalyzed click cyclization reactions. The amphiphilic HA derivatives dissolved in water and formed self-assemblies in which the near-infrared dyes were tightly packed and arranged to form dimers or H-aggregates. By irradiating an aqueous solution of HA derivatives with near-infrared light, photoacoustic signals were detected along with fluorescence emission. Self-assemblies consisting of HA derivatives could smoothly accumulate in tumor tissues by passive tumor targeting. By utilizing HA derivatives as a contrast agent, tumor sites were clearly visualized by optical imaging as well as by photoacoustic tomography.
The reminiscence bump is the effect that people recall more personal events from their teenage period than from adjacent lifetime periods. The effect is generally found in studies that divide the results of participants, who were at least 40 years old, into age bins of 10 years. In this study, the temporal distribution of autobiographical memories of Japanese young and middle-aged adults was examined. Because the questionnaire was presented on the internet, many participants could take part (N = 252). By dividing the personal events into smaller age bins and applying a mathematical method that corrects for the increased recall of recent events, a reminiscence bump could be identified in the memories of young adults. The location of the reminiscence bump of young adults was similar to the location of the reminiscence bump of middle-aged adults.j pr_451 86..96
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