Anionic copolymerization of β-lactones in correlation with the mode of fission. studies on the syntheses of aliphatic polyesters. XI

The copolymerization behavior of β-propiolactone (PL) and α.α-bischloromethyl β-propiolactone (α-BCPL) is correlated with the mode of fission. With sodium acetate as catalyst, the formation of β-acetoxy propionic acid at the initiation reaction was observed and α-BCPL was more than five times as reactive as PL in copolymerization. Thus propagation by carboxylate anion through alkyl-oxygen fission was presumed in the case of pyridine and the acetate of Na, Li, and Mg as catalyst. On the other hand, the formation of ethyl β-hydroxy propionate and the decreased reactivity of α-BCPL in copolymerization was observed with magnesium and aluminum ethoxide as catalyst. In the case of the ethoxide of Na, Li, and Al, and Et₂Mg or Et₃Al as catalyst, propagation by alkoxide anions through acyl-oxygen fission of the coordinated lactones was presumed.     

Vacuolated cell mesothelioma of the pericardium resembling liposarcoma: a case report

We report a case of localized pericardial mesothelioma with unusual histological features in a 44-year-old woman. Her radiological imagings showed an 11-cm pericardial tumor, between the heart and aortic arch. Microscopically, the tumor was predominantly composed of vacuolated cells and vaguely reminiscent of well differentiated "lipoma-like" liposarcoma, but only small foci of the tumor showed the papillotubular configuration. Histochemically, the tumor cells contained hyaluronic acid in the vacuoles but no lipids. Immunohistochemically, they showed immunoreactivity for cytokeratin, calretinin, vimentin, and epithelial membrane antigen. Ultrastructural study showed that the vacuoles of the tumor cells were intracytoplasmic lumina. The intracytoplasmic lumina and the surface membranes of the tumor cells had many long and slender microvilli with focal bush-like appearance. Desmosomes between adjacent cells were occasionally observed. To our knowledge, this is the first case report of epithelial type mesothelioma predominantly composed of vacuolated tumor cells, microscopically mimicking liposarcoma.     

p53 protein overexpression and K-rascodon 12 mutation in pancreatic ductal carcinoma: Correlation with histologic factors

The correlation of p53 protein overexpression and the K-ras codon 12 mutatlon wlth histologlc type, grade of cytologic atypla, depth of lnvasion and other histologlc prognostic factors was studied In paraffin sectlons from 43 ductectatic-and 70 solid-type pancreatic ductal carcinomas. Overexpression of p53 was found in 23.3% (10143) of ductectatic carcinomas (17.2% of intraductal and 35.7% of lnvaslve carclnomas) and in 61.4% (43/70) of solid carcinomas. In ductectatic cancers, p53 overexpression was detected In 14.8% (4/27) of carcinomas wlth lowgrade atypla (CAL), 50.0% (5110) of carcinomas wlth high-grade atypla (CAH) and in 16.7% (In) of mixed low- and hlgh-grade cancers. In the last group, expression was restricted to an area of CAH. In solld cancers, p53 overexpression did not dlffer by histologic type or grade. Overexpresslon of p53 and K-ras mutatlons did not correlate with histologlc prognostic factors (lymphatic, venous and perineural Invasion, and lymph node metastasls) in ductectatlc and solld cancers or depth of invasion of solld carclnomas. Our data suggest that p53 alteratlon occurs at an early intraductal stage of solld carcinoma, irrespectlve of cellular atypla, but Is low in ductectatic CAL and becomes hlgher In ductectatlc CAH. K-ras mutatlon, present In a high percentage of tumors of all groups and not correlating with the factors above, showed no changes In frequency with tumor progression.     

Synthesis and permeation behavior of membranes from segmented multiblock copolymers containing poly(ethylene oxide) and poly(β-benzyl L-aspartate) blocks

Novel segmented multiblock copolymers ( 7 ) were synthesized by linking poly(ethylene oxide) (PEO) blocks with poly(β-benzyl L -aspartate)(PBLA) blocks via urethane and urea bonds, which were formed by the reaction of 4,4′-methylenediphenyl isocyanate ( 5 ) with the terminal hydroxyl groups of α-hydro-ω-hydroxypoly(oxyethylene) ( 4 ) and the terminal amino groups of poly(β-benzyl L -aspartate)-block-iminohexamethyleneimino-block-poly(β-benzyl L -aspartate) ( 3 ) [prepared from 1,6-hexanediamine ( 1 ) and β-benzyl L -aspartate N-carboxy anhydride ( 2 )], respectively. Membranes with various water contents were obtained from these copolymers by changing the lengths of the PEO and PBLA segments. The study of the permeation of 1-phenyl-1,2-ethanediol, vitamin B₁₂ and myoglobin through the membranes showed a high dependency of the permeability on the molecular weight of the solutes.     

An autoradiographic study of binding of iodinated spider toxin to lobster muscle

Distribution of the binding sites of Joro spider toxin (JSTX), a specific inhibitor of the glutamate receptors in the crustacean neuromuscular synapse, was studied by using autoradiography. JSTX was synthesized and made radioactive by conjugation with iodine-125. 125I-JSTX irreversibly blocked the excitatory postsynaptic potentials of the lobster neuromuscular synapse in a similar manner as the natural spider toxin. Light microscopic autoradiography of 125I-JSTX treated muscle showed sporadic aggregates of reduced silver grains on the surface of muscles. Electron microscopy of adjoining ultrathin sections revealed that these spots corresponded to the fraction of sarcolemma apposed to axonal terminals with or without synaptic junctional profiles. This finding gives morphological support to the formulation that JSTX binds to the glutamate receptor-ion channel molecules.     

Combined treatment of pelvic exenterative surgery and intra-operative pelvic hyperthermochemotherapy for locally advanced rectosigmoid cancer: Report of a case

A huge rectosigmoidal cancer which extended into the urinary bladder in a 64-year-old man is herein described. The tumor occupied the pelvic and lower abdominal cavities, while the rectosigmoid was totally obstructed. No hepatic or pulmonary metastasis was evident. The ventral and flank sides of the peritoneum in the right lower abdomen, right common iliac vessels, bilateral ureters, terminal ileum, cecum, ascending colon, and urinary bladder were all directly invaded by the tumor, but the aorta, sacrum, and lower rectum were free of cancer. Consequently, an anterior pelvic exenteration was carried out along with an ileal conduit and a right hemicolectomy. Immediately after the exenteration, intra-pelvic hyperthermochemotherapy was performed using a 46–47°C perfusate containing 40 g/ml of mitomycin C (MMC) and 200 g/ml of cisplatin (CDDP), for 90 min, in an attempt to prevent any further local recurrence. A right hemicolectomy and a permanent colostomy were done simultaneously with the hyperthermia treatment. After an uneventful postoperative course, the patient was prescribed adjuvant chemotherapy, i.e., two administrations of 17 mg/m² and 21 mg/m² of MMC, and ten doses of 710 mg/m² of 5-fluorouracil (5-FU) followed by five doses of 535 mg/m² of 5-FU. At the time of this writing, the patient is still alive without recurrence at 21 months after surgery.     

Shock and acute organ dysfunction

Multiple trauma, hemorrhage, and sepsis may produce various kinds of shock, and such a host as shock could not be controlled and may easily fall into multiple organ dysfunction. Although those mechanisms on the pathogenesis of these sequential inflammatory responses have been clarified recently, the clinical outcome of such patients suffering from severe sepsis and multiple organ dysfunction is still very low. This inflammatory response against the insult shows a sequential manner; cardiovascular system failure, renal system failure, respiratory system failure, central nervous system failure, and finally, hepatic failure. However, the host response to the insult is a kind of defense against the invasion, and the clinical goal might be to stabilize hemodynamic system, metabolic system, and immunologic system. To achieve hemodynamic homeostasis, we use catecholamines and blood transfusion to improve the oxygen supply to important organs and enhance tissue repair. For metabolic homeostasis, early administration of hyperalimentation may be needed, either parenterally or enterally. Enteral feeding may also provided a route for bacterial translocation. To achieve immunologic homeostasis, prophylactic antibiotic administration and metabolic support may be required and should also protect against infection as a secondary invasion. This review explains these mechanisms in terms of the relationship between shock and organ dysfunction and the general features of clinical management.     

Excimer laser-induced hydroxyl radical formation and keratocyte death in vitro

PURPOSE: To characterize the type of reactive oxygen species (ROS) produced by excimer photoablation of aqueous solutions and to show the effects of ROS and antioxidants on corneal stromal cells in vitro. METHODS: Electron spin-resonance spectroscopy was performed using the spin-trapping agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO) for the detection of the superoxide anion and the hydroxyl radical in an acellular DMPO solution irradiated with the excimer laser. Hydroxyl radicals were produced by the Fenton reaction in vitro by the mixture of hydrogen peroxide and ferrous iron (Fe2+), and the effects on cultured corneal fibroblasts were observed by fluorescent microscopy using the cell death marker, propidium iodide (PI) and TdT-mediated dUTP nick-end labeling (TUNEL). RESULTS: Excimer photoablation of a 1% DMPO solution produced a species-specific spin-trapping adduct for the hydroxyl radical ('OH), but not for the superoxide anion or other unidentified free radical. The signals were inhibited dose dependently by the hydroxyl radical scavenger dimethylsulfoxide (DMSO) and an L-ascorbic acid analogue, EPCK-1. The production of *OH in the supernatant of cultured rabbit corneal fibroblasts by the Fenton reaction caused an increase in PI (+) and TUNEL (+) cells by 90 minutes, which was significantly inhibited by the addition of DMSO. CONCLUSIONS: Hydroxyl radicals may be partly responsible for stromal fibroblast cell apoptosis after excimer photoablation.     

Morphology and barrier function of the corneal epithelium after penetrating keratoplasty: association with original diseases, tear function, and suture removal.

PURPOSE: To study changes in structure and barrier function of the corneal epithelium after penetrating keratoplasty. METHODS: Sixty-nine eyes of 56 patients undergoing penetrating keratoplasty were studied. Fifty-six age-matched normal eyes served as controls. Corneal epithelial structure was studied by using specular microscopy. Barrier function of the corneal epithelium was examined by slit-lamp fluorophotometry. Vital staining, tear function, and corneal sensitivity also were examined. RESULTS: Fluorescein and rose bengal staining scores, incidence of elongated cells, the mean epithelial area, and mean fluorescein uptake were significantly increased in postkeratoplasty eyes compared with controls. Original disease influenced the results of barrier function, where keratoconus revealed better function than bullous keratopathy or corneal scar. However, no such differences were noted in epithelial structure. Six eyes with absence of palisades of Vogt had revealed significantly increased epithelial area and fluorescein uptake. Removal of the running suture caused a decrease in elongated cells and epithelial cell area without significant changes in barrier function. CONCLUSION: Corneal epithelial structure was significantly impaired in postkeratoplasty eyes. Epithelial barrier function of postkeratoplasty eyes was influenced by original diseases. Removal of sutures improves epithelial structure but not barrier function.