Effect of alkyl groups on the rate constants of propagation and termination in the radical polymerization of dialkyl itaconates

Polymerization of dialkyl itaconates with dimethyl azoisobutyrate ( 5 ) was studied in benzene at 50°C by means of electron spin resonance (ESR). The monomers used are dimethyl ( 1 ), diethyl ( 2 ), dibutyl ( 3 ) and di-2-ethylhexyl ( 4 ) itaconates. All the polymerization systems involve ESR-observable propagating polymer radicals under the actual polymerization conditions. The polymerization rate (R_p) and degree of polymerization of the resulting polymer increase in going from shorter to longer alkyl groups. The ESR-determined rate constants of propagation (k_p) and termination (k_t) decrease as the alkyl chain becomes longer. k_p of 1 is 3,3 times higher than that of 4 , while k_t of 1 is 590 times higher than that of 4 . Thus, the steric effect due to the alkyl group suppresses much more termination than propagation, leading to the fact that R_p increases as the alkyl group becomes larger.     

Preemptive analgesia by zaltoprofen that inhibits bradykinin action and cyclooxygenase in a post-operative pain model

The post-operative pain state results from a barrage of primary afferent inputs exposed to products of tissue damage such as bradykinin and prostaglandins and the central sensitization by the continuing inputs. This provides the rationale for preemptive analgesia, whereby the blockade of primary afferent inputs prior to injury may result in a reduction of post-operative pain. 2-(10,11-dihydro-10-oxo-dibenzo[b,f]thiepin-2-yl) propionic acid (zaltoprofen) is a unique compound that inhibits cyclooxygenase (COX) and exhibits anti-bradykinin activity. The present study evaluated the preemptive analgesic effect of zaltoprofen in a post-operative pain model produced by plantar incision. When orally, but no intrathecally, administered 30 min prior to incision, zaltoprofen significantly increased the withdrawal threshold 2 h and 1-3 days after incision at 10 mg/kg. While the bradykinin B1 antagonist des-Arg10-HOE-140, the selective COX-1 inhibitor SC-560, and the selective COX-2 inhibitor celecoxib did not affect post-operative pain, the B2 antagonist HOE-140 dose-dependently relieved the post-operative pain at 2-200 microg/kg with a time course similar to that of zaltoprofen. The B2 receptor mRNA was expressed in the hindpaw and the expression did not change before and 24 h after surgery. These results suggest that zaltoprofen produces the preemptive analgesic effect peripherally by blocking the B2 pathway.     

Anterior Transhepatic Approach for Isolated Resection of the Caudate Lobe of the Liver

RID=" ID=" <E5>Correspondence to:</E5> J. Yamamoto, M.D.     

Intestinal Behçet's disease associated with non-Hodgkin's lymphoma

A 45-year-old man with intestinal Behçet's disease noticed an enlarged right cervical lymph node, and was diagnosed with diffuse large cell type, non-Hodgkin's lymphoma. The intrapelvic lymph tract was markedly deformed because of recurrent ileocecal ulceration, and conventional lymphoscintigraphy with a common tracer did not abolish the suspicion that lymphoma cells may have invaded the lymph nodes. Dynamic lymphoscintigraphy with a new tracer,^99mtechnetium-diethylene triamine pentaacetic acid-human serum albumin, because of its high detection sensitivity, was very useful for excluding this suspicion, and for determining the clinical stage of lymphoma. Combination induction chemotherapy led to complete remission without any adverse effects, but subsequent supportive therapy with same protocol could not be completed because of progression of the intestinal lesions. Special management for the intestinal lesions, such as bowel rest, may be essential with chemotherapy for patients with intestinal Behçet's disease.     

Deregulation of G1/S transition is a common event in carcinoma of the ampulla of vater

BACKGROUND/AIMS: Aberrant expression of cell cycle regulators and subsequent deregulation of G1/S transition is one of the most important characteristics of human cancer. The aim of this study was to determine the overall pattern of deranged expression of the cell cycle regulators involved in the G1/S transition in ampullary carcinoma. METHODOLOGY: Using immunohistochemistry, we investigated the expression of p21WAF1/CIP1, p27Kip1, p16INK4, cyclin D1, cyclin E, pRb and p53 in 14 resected specimens of ampullary carcinoma and defined the proliferative activity of each tumor by quantifying Ki-67 antigen. RESULTS: Decreased expression of p21WAF1/CIP1, p27Kip1, and p16INK4 was detected in 6 (43%), 11 (79%), and 4 (29%) tumors, respectively. Four tumors (29%) overexpressed cyclin D1 and 8 (57%) overexpressed cyclin E. Eight tumors (57%) overexpressed pRb. Aberrant accumulation of p53 was observed in 10 (71%) of the tumors. Overall, the expression of two or more of these cell cycle regulators was altered in all of the 14 tumors. Decreased p21WAF1/CIP1 expression was related to higher TMN stage (P = 0.04) and lymphatic invasion (P = 0.04). The proliferative index was higher in tumors with decreased p27Kip expression (P = 0.005), and in tumors with cyclin E overexpression (P = 0.06). CONCLUSIONS: Our observations suggest that deregulation of G1/S transition is a very common event in ampullary carcinoma, and that altered expression of cell cycle regulators is associated with the aggressive behavior of this tumor. Correcting the G1/S transition regulatory machinery may provide a novel therapy for this malignancy.     

Phonatory function following esophagectomy for esophageal cancer

BACKGROUND/AIMS: Quality of life can be adversely affected in many patients who suffer phonation disorders such as hoarseness and dysphonia following esophagectomy. The present study investigated postoperative phonation disorders in 15 patients who underwent esophagectomy for esophageal cancer. METHODOLOGY: None of the patients had signs of hoarseness before or after surgery. Aerodynamic testing to assess phonatory function testing and laryngoscopy for observing laryngeal movements were performed before and after surgery. As a control, the same tests were conducted in 20 patients treated for gastric cancer by gastrectomy. RESULTS: For esophagectomy patients, mean postoperative flow rate was significantly increased and maximum postoperative phonation time was significantly decreased after operation. Laryngoscopy confirmed postoperative paralysis of left laryngeal movements and excessive adduction of the right, unaffected vocal cord during phonation in 8 of 15 esophagectomy patients, although hoarseness was not reported by any patient. No significant changes were observed for mean postoperative flow rate or maximum postoperative phonation time following surgery in gastrectomy patients. CONCLUSIONS: Surgical procedures in the vicinity of the recurrent laryngeal nerve appear to be the cause of postoperative phonation disorders in patients undergoing esophagectomy for esophageal cancer, and these disorders can occur in the absence of symptoms such as hoarseness and dysphonia.