bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pancreatic Solid‐cystic‐papillary Tumor: Clinicopathologic Features in Eight Patients from Hong Kong and Review of the Literature
Authors: Lam King Y. , Lo Chung Y. , Fan Sheung T. 
Published: August 2002

Abstract.Solid‐cystic‐papillary tumors (SCPTs) of the pancreas are rare. The clinicopathologic features and pathogenesis of these tumors have attracted a number of investigations, but the results remain unclear. We investigated the clinicopathologic data, immunohistochemical expression of the pan‐endocrine markers, hormones, steroid receptors, and p53 overexpression in pancreatic SCPTs from eight Chinese patients (seven women, one man) collected over a 24‐year period. They accounted for 2.5% of the primary pancreatic tumors. The tumors were seen in young women (mean age 27 years). They were large (mean size of resected tumor was 8.4 cm), benign, had solid and cystic areas, and were evenly distributed in the pancreas. The main differential diagnosis was pancreatic endocrine tumor. The tumors were negative for pan‐endocrine markers, hormones, estrogen receptor, progesterone receptor, and p53. To date, 452 pancreatic SCPTs have been documented in the English literature. They occurred in patients of different ethnic groups, particularly in non‐Caucasians. The tumors were frequently noted in young females. Uncommon cases of malignant pancreatic SCPTs were often found in older men and had indolent behavior. It was concluded that pancreatic SCPTs have distinct clinicopathologic characteristics. The present observations, together with a review of the literature suggests that overexpression of p53 or estrogen receptor is not important in the pathogenesis of pancreatic SCPTs.
Pulmonary Arteriovenous Fistula: Presentation, Diagnosis, and Treatment
Authors: Pick Adrian , Deschamps Claude , Stanson Anthony W. 
Published: August 2002

Abstract.Pulmonary arteriovenous fistulas (PAVFs) are rare vascular malformations of the lung. There is a strong association with Rendu‐Osler‐Weber disease. Although most patients are asymptomatic, PAVFs can cause dyspnea from a right‐to‐left shunt. They can also bleed and result in hemoptysis and hemothorax. Because of paradoxical emboli, various central nervous system complications have been described including stroke, and brain abscess. Currently, spiral computed tomography offers the most practical method for establishing the presence of PAVFs. Most patients should be treated. Therapeutic options include angiographic embolization with metal coils or balloon occlusion and surgical excision. Angiographic treatment has become the mainstay of therapy for most patients during the last decade. It is less invasive and can be repeated easily. Surgery, which usually consists of a conservative lung resection, is associated with low morbidity and a low recurrence rate. Both therapeutic approaches are discussed. The Mayo Clinic surgical experience of the last 20 years for PAVFs is presented.
Curative Resection of Colorectal Adenocarcinoma: Multivariate Analysis of 5‐Year Follow‐up
Authors: Han‐Shiang Chen 
Published: August 2002

Abstract.The purpose of this study was to evaluate the influence of clinicopathologic factors on colorectal cancer, especially the age factor. From 1986 to 1992 a total of 2082 cases of colorectal cancers underwent operation in our institution. After exclusion of familial adenomatous polyposis, multiple cancer, Dukes' D stage, and nonadenocarcinoma patients, there were 1124 patients with single colorectal adenocarcinoma who had undergone curative operation; 1110 cases were included in the study after exclusion of surgical mortalities (14 cases, 1.2%). Age distribution ranged from 19 to 91 years (mean 58 years). The patients were divided into three age groups: < 40 years (grade 1), 40–69 years (grade 2), ≥ 70 years (grade 3); other clinicopathologic factors including gender, tumor gross type, location, pathology, and stage were also evaluated in the study. The colonic/rectal cancer ratio was 1.00:1.74, and that of the male/female distribution was 1.00:0.84. The overall 5‐year cancer‐free rate was 69.9% after curative resection. The young age (< 40 years) patients comprised more women (53.6%) and had a colon location in 41%. Although they had a higher percentage of scirrhous type lesions (1.8%), worse histology (17%), and more advanced stage (49.1%) than the older groups, their survival rate was only slightly lower than the other two groups (67% vs. 70% and 72%, respectively), which was not statistically significant (p= 0.83). By univariate analysis, the factors that influenced the 5‐year cancer‐free rate were gender (p= 0.031), tumor location (p= 0.003), gross type (p= 0.000), pathology (p= 0.000), and stage (p= 0.001). The independent factors determined for the 5‐year cancer‐free rate after multivariate analysis were similar to those assessed by univariate analysis. There 5‐year survival of colorectal adenocarcinoma was not poorer in young patients. Poor survival factors were male gender, rectal location, scirrhous type, poor and mucinous histology, and advanced stage (Dukes' C) found at curative resection for colorectal adenocarcinoma.
Video‐assisted Thoracoscopic Lobectomy Achieves a Satisfactory Long‐term Prognosis in Patients with Clinical Stage IA Lung Cancer
Authors: Sugi Kazuro , Kaneda Yoshikazu , Esato Kensuke 
Published: August 2002

AbstractWe designed a prospective trial to determine the long‐term prognosis of video‐assisted thoracoscopic (VATS) lobectomy versus conventional lobectomy for patients with clinical stage IA (T1N0M0) lung cancer. Between January 1993 and June 1994, 100 consecutive patients with clinical stage IA non‐small cell lung carcinoma underwent either conventional lobectomy through an open thoracotomy (open group; n= 52) or VATS lobectomy (VATS group; n= 48). Lymph node dissections were performed in a similar manner in both groups. No significant differences were observed in the number of dissected lymph nodes between the 2 groups. Pathologic N1 and N2 disease was found in 3 and 1 patients, respectively, from the open group, and in 2 and 1 patients, respectively, from the VATS group. During the follow‐up period, distant metastases and local or regional recurrences developed in 7 and 3 of the open group patients, respectively, and in 2 and 3 of the VATS group patients, respectively. Two and one of the open and VATS group patients developed second primary cancers, respectively. The overall survival rates 5 years after surgery were 85% and 90% in the open and VATS groups, respectively (log‐rank test, p= 0.74; generalized Wilcoxon test, p= 0.91). VATS lobectomy with lymph node dissection achieved an excellent 5‐year survival, similar to that achieved by the conventional approach.
Clinicopathologic Correlation of p53 Protein Overexpression in Adenoma and Carcinoma of the Ampulla of Vater
Authors: Park Sun Hoo , Kim Yong Il , Park Yong Hyun , Kim Sun Whe , Kim Ki Whan , Kim Yong Tae , Kim Woo Ho 
Published: August 2002

AbstractIt has been well documented that ampullary carcinoma arises from a precancerous lesion, but there have been few studies concerning changes at the molecular level during the adenoma‐carcinoma sequence. In this study, p53 overexpression during the progression of carcinoma was compared and the relation between p53 expression and prognosis was analyzed. Ninety‐four cases of adenocarcinoma of the ampulla of Vater were reviewed histopathologically and examined for overexpression of p53 protein using the DO‐7 (mouse monoclonal; DAKO, Glostrup, Denmark) antibody. The correlation of p53 overexpression with the existence of adenoma, clinical stage, histologic grade, and overall survival was investigated. The proportion of p53‐positive cases among normal mucosa, adenoma, early stage carcinoma (I and II), advanced stage carcinoma (III and IV), and metastatic lesion was 0% (0/94), 14.3% (6/42), 32.3% (20/62), 53.1% (17/32), and 63.3% (19/30), respectively. The existence of adenoma or histologic grade of carcinoma did not correlate with p53 overexpression. The carcinoma having adenomatous component was more common in early stages (54.8% in stages I and II, 25% in stages III and IV; p= 0.006) and in well‐differentiated carcinoma (p= 0.001). The existence of adenoma or p53 overexpression did not independently correlate with prognosis. In contrast, the p53 overexpressed group without adenoma showed a worse prognosis than the remaining patients (p= 0.0006) and this trend was still demonstrable when the groups were compared stage by stage. In ampullary carcinoma, p53 abnormality occurs during malignant transformation from the adenoma and continues during the tumor progression in carcinoma. The clinical prognosis of de novo carcinomas with p53 overexpression was worse than that of the remaining patients.
Combined Omental Pedicle Grafts and Thoracodorsal Axial Pattern Flaps for the Reconstruction of Chronic, Nonhealing Axillary Wounds in Cats
Authors: Lascelles B. Duncan X. , White Richard A. S. 
Published: August 2002

Objective—To assess the results of an omental pedicle graft in combination with a thoracodorsal axial pattern flap for the reconstruction of chronic nonhealing axillary wounds in 10 cats caused by forelimb entrapment within a collar.Study Design—A prospective, clinical trial.Animals Used—Ten client‐owned domestic shorthair cats.Methods—Routine biochemical and hematologic evaluation was performed on each cat, and all were tested for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV). Microbial culture was performed on samples from the wounds. After surgical debridement, omentalization using a vascular pedicle of greater omentum, and closure of the chronic axillary wounds, using a thoracodorsal axial pattern flap, was performed. All excised tissue was examined histologically.Results—The sex distribution was 7 males and 3 females, with a mean age of 3.5 years. The cats had undergone a median number of 3 previous repair attempts over a 1.5‐ to 25‐month period before referral (mean, 10.2 months). No hematologic or biochemical abnormalities were noted apart from moderately elevated creatine kinase and aspartate transaminase concentrations in some cats. All cats were negative for FIV and FeLV. Histologic examination of resected tissue revealed hair (foreign body) in 2 cats and an unidentified foreign‐body reaction in 3 other cats. Complete healing occurred in all cats (mean follow‐up period of 21.7 months), with 2 cats requiring further surgery: 1 for flap dehiscence at 4 days after surgery, and 1 for donor‐site dehiscence at 4 days after surgery. One other cat developed a large seroma in the axilla that resolved by 10 days following surgery.Conclusion—The use of an omental pedicle graft in combination with a thoracodorsal axial pattern flap is the first consistently successful 1‐step technique for the management of chronic nonhealing axillary wounds in cats.
Regulation of Cytochrome c Oxidase by Adenylic Nucleotides. Is Oxidative Phosphorylation Feedback Regulated by its End‐Products?
Authors: Beauvoit Bertrand , Rigoulet Michel 
Published: August 2002

AbstractCytochrome c oxidase, which catalyzes an irreversible step of the respiratory chain, is one of the rate‐controlling steps of oxidative phosphorylation on isolated mitochondria. The rate of electron transfer through the complex is primarily controlled by the associated thermodynamic forces, i.e., the span in redox potential between oxygen and cytochrome c and the protonmotive force. However, the electron flux also depends on the various kinetic effectors, including adenylic nucleotides. Although the number of binding sites for ATP and ADP on cytochrome oxidase is still a matter of debate, experiments performed on the solubilized and reconstituted enzyme provide strong functional evidence that the mammalian cytochrome c oxidase binds adenylic nucleotides on both sides of the inner membrane. These effects include modification in cytochrome c affinity, allosteric inhibition and changes in proton pumping efficiency. Immunological studies have pointed out the role of subunit IV and that of an ATP‐binding protein, subunit VIa, in these kinetic regulations. In yeast, the role of the nuclear‐encoded subunits in assembly and regulation of the cytochrome c oxidase has been further substantiated by using gene‐disruption analysis. Using a subunit VIa‐null mutant, the consequences of the ATP regulation on oxidative phosphorylation have been further investigated on isolated mitochondria. Taken together, the data demonstrate that there are multiple regulating sites for ATP on the yeast cytochrome oxidase with respect to the location (matrix versus cytosolic side), kinetic effect (activation versus inhibition) and consequence on the flow‐force relationships. The question is therefore raised as to the physiological meaning of such feedback regulation of the respiratory chain by ATP in the control and regulation of cellular energy metabolism.
New Thermostable Systems: 1. Mechanism and Kinetics of Polycondensation and Characterization of Fluoro-Nadimide End-Capped Oligomers
Authors: Loustalot Marie Florence Grenier , Billon Laurent , Sillion Bernard 
Published: August 2002

The reactivity of monomers in PMR (polymerization of monomeric reactants) mixtures has been investigated in methanol at room temperature. The monomers used were three aromatic diamines, meta-phenylene diamine ( mPDA), para-phenylene diamine ( pPDA), the 9, 9-bis (4-amino phenyl) fluorene (Cardo diamine), hexafluoroisopropylidene-2, 2 bis phthalic ether (HFDE) and nadic anhydride mono methyl ester (NE). Using titration, and 13C and 19F NMR, it was found that NE rapidly reacts with the three aromatic diamines to yield bisnadimides; the corresponding acid-amide intermediates were not detected. The diester HFDE, on the other hand, reacts only very slowly with the same diamines at room temperature in methanol. Telechelic polyimides with nadic terminations were prepared from these monomers and characterized with liquid phase 1H and 13C NMR and HPLC. This physico-chemical study showed that during synthesis, the endo (N) nadimides isomerize giving off a mixture of endo endo (NN), endo exo (NX) and exo exo (XX) end groups. In addition, a fine high-performance liquid chromatography analysis led to the separation of oligomers as a function of their polymerization degree, and for each molecular weight a mixture of isomeric chain end groups NN, NX, XX were separated.
Hyperbranched Aramids by the A2 + B3 versus AB2 Approach: Influence of the Reaction Conditions on Structural Development
Authors: Monticelli Orietta , Mariani Alberto , Voit Brigitte , Komber Hartmut , Mendichi Raniero , Pitto Valentina , Tabuani Daniela , Russo Saverio 
Published: August 2002

Hyperbranched aromatic polyamides (pPDT) from A2 ( p-phenylene diamine)+ B3 (trimesic acid) reactants have been prepared using direct polycondensation in solution. The influence of various polymerization parameters on the polymer structure development and the sol content, as well as on gel formation, has been thoroughly investigated. Prior to the attainment of the gel point, whose occurrence is linked quite strongly to the reaction conditions, the resultant hyperbranched polymers are fully soluble even at room temperature, not only in concentrated H2SO4, but also in aprotic polar solvents (DMF, NMP, DMAc, DMSO). At 80°C, under typical experimental conditions, gel formation starts just under 120 min. At a higher temperature (115°C), the attainment of crosslinking reactions is accelerated (gel point occurs at about 20 min). Both the presence of added salt (LiCl) to the reaction medium at 80°C and the use of highly purified reagents promotes earlier gel occurrence. By increasing the molar ratio of primary amino to carboxyl groups from two-thirds to one, the network formation is delayed. A molar ratio of 1/2 leads to the formation of oligomers only. Both the polymer structure development and the degree of branching of pPDT have been evaluated by NMR spectroscopy as functions of reaction conditions. As compared to pPDT, polymers prepared from the homologous AB2 monomer show similar intrinsic viscosity and glass transition temperature, but higher molecular weights and distinct differences in the relative ratio of the various structural units. The lyotropic and thermotropic behaviour of both polymers has been found.
Synthesis and Phase Separation Behaviour of High Performance Multiblock Copolymers
Authors: Pospiech Doris , Häußler Liane , Eckstein Kathrin , Komber Hartmut , Voigt Dieter , Jehnichen Dieter , Friedel Peter , Gottwald Antje , Kollig Wolfram , Kricheldorf Hans R 
Published: August 2002

The phase separation behaviour of block copolymers of the type (A–B) n(segmented block copolymers, multiblock copolymers) containing segments with different degrees of flexibility was investigated using a stepwise variation of the incorporated blocks A and B. Amorphous/rigid blocks (polysulfone segments) were systematically combined with amorphous/flexible blocks (poly(tetramethylene glycol), semiflexible/nematic blocks (different kinds of aromatic polyesters and poly(ester imides) as well as semicrystalline fluorinated polyester blocks). All multiblock copolymers were synthesized using a conventional transesterification polycondensation in the melt and the polycondensation results are discussed. The phase separation in the synthesized block copolymers was investigated both experimentally and theoretically. Flory–Huggins interaction parameters of the block copolymers were calculated and used together with mean field calculations in order to understand the phase separation behaviour of all block copolymers correlated to their chemical structure. On the other hand, the onset of phase separation in a series of block copolymers with a systematic variation of block molecular weights was examined experimentally, mainly by DSC and SAXS. Finally, the question is discussed whether or not the degree of phase separation in the investigated systems determines the properties of the polymers or not. This is for example outlined for the mechanical properties and, in particular, the surface properties of fluorinated block copolymers.
Surface Contamination of Some Materials of the Space Station ‘MIR’
Authors: Skurat V E , Tantsyreve G D , Beriozkina N G , Volkov A V , Jigatch A N , Leipunsky I O , Pshechenkov P A , Samsonov P V , Toropov V P , Demidov S A , Naumov S F , Sokolova S P 
Published: August 2002

About 60 samples of various materials exposed to low Earth orbit (LEO) conditions for 997 days on board the orbital space station ‘Mir’ were investigated. The aim was to determine the properties of the contamination layers formed during LEO exposition. The following methods were used: optical and scanning electron microscopy, local x-ray microanalysis, secondary ion mass spectrometry in fast atom bombardment ionization mode, electron spectroscopy for chemical analysis, temperature programmed desorption mass spectrometry, x-ray phase analysis, spectral reflectance, solar absorbance and relative emittance measurements. Two effects were observed for all samples: the formation of contamination deposits and the erosion of the substrate–original surface. The relative contribution of both effects changes depending on the sample type and on exposure conditions. The deposit thickness varies on the sample surface over a very wide range (at least five decimal orders of magnitude), changing from values exceeding 100 μm to values of less than 2 nm (possibly these regions do not contain any deposit at all). The main element of contamination is silicon; the others are potassium and calcium. Evidence of a chemical reaction between the Teflon FEP substrate and the contamination was observed.
Functionalized Poly-Imide–Amides: Molten State Reaction Mechanisms and Kinetics
Authors: Grenier-Loustalot Marie-Florence , Trillaud Marc , Grenier Philippe 
Published: August 2002

Molten state polymerization reaction mechanisms and kinetics of telechelic polyimide–amides (PIA) were investigated. We conducted a basic study of the reactions of these functionalized systems as a function of the chemical structure of the polymer. Since reaction products very rapidly became insoluble, the study was carried out on model compounds characteristic of reactive chain ends. The data obtained were applied to the study of industrial prepolymers. Different model compounds were synthesized and studied in the temperature range of 100 to 300 °C using such physicochemical methods as HPLC, 1H and 13C NMR (liquid and solid), FTIR and DSC. We were thus able to determine a number of precise parameters characteristic of the different reactions occurring (isomerization, crosslinking, co-reactions and side reactions). The results were applied to the study of 1500 molecular weight prepolymers and preimpregnated carbon fibres.
Synthesis, Characterization and Glass-Reinforced Composites of Acetone–Formaldehyde–Phenol Resins
Authors: Patel Hasmukh S , Dixit Bharat C 
Published: August 2002

Acetone–formaldehyde (AF) resin having the methylol group (–CH2OH) has been prepared and characterized. The condensation of AF resin with phenol (P) was carried out in the presence of alcoholic alkali catalyst at varying ratios of AF:P, namely 1:1, 1:1.5 and 1:2. The resultant AFP resins were characterized by elemental analysis, IR spectral studies, number average molecular weight ( Mn) estimated by non-aqueous conductometric titration, and thermogravimetry. The curing study of AFP resins with hexamethylene tetramine (HMTA) was monitored by differential scanning calorimetry (DSC) and kinetic parameters were evaluated. Glass-reinforced composites based on the AFP–HMTA system have also been prepared and characterized.
Gender, parental and peer influences upon science attitudes and activities
Authors: Breakwell Glynis M. , Beardsell Sue 
Published: August 2002

This paper explores the extent to which variance in science attitudes and involvement in science activities may be attributable to gender, parental and peer influences upon 11-14 year olds in the UK. The data presented are derived from a sample of 391 pupils drawn at random, but stratified by age and gender, from Local Education Authority schools (i.e. schools within the state sector where parents make no direct payments for education). A self-completion questionnaire was administered to the pupils in school. Attitudes toward scientific change, involvement in scientific extra-curricular activity, liking and performance in school science subjects, and participation in peer youth culture were indexed, in addition to estimates of the amount of positive regard for science expressed by peers and parents. Boys had more positive attitudes to science and greater levels of participation in scientific extra-curricular activities. They also reported performing better at school science than girls. A positive attitude to science was strongly positively related to having a father and mother who support science, coming from a lower socio-economic family background, being male, and having scientific peers. Greater involvement in scientific extra-curricular activities was predicted by having a father who supports science, having parents who engage in activities jointly with their children, and having scientific peers. In terms of predicting participation in science, liking of it and success at it, these data lead to the conclusion that both parental and peer support are influential. Though it does seem that they are relatively more important in predicting variance in attitudes to science in society than as indicators of liking of or performance at school science. The problems involved in estimating whether commonly reported gender effects are mediated through peer or parental support are discussed.