bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of problem drinking on employment
Authors: Feng Weiwei , Zhou Wei , Butler J.S. , Booth Brenda M. , French Michael T.
Published: August 2002

Social cost studies report that alcohol use and misuse impose a great economic burden on society, and over half of the total economic costs are estimated to be due to the loss of work productivity. Controversy remains, however, as to the magnitude and direction of the effects of alcohol consumption on productivity. Furthermore, most of the studies have looked at the relationship between problem drinking and wages. This paper investigates the impact of problem drinking on employment by analysing a random sample of men and women of prime working age from six Southern states in the US (Alabama, Arkansas, Georgia, Louisiana, Mississippi and Tennessee). The data set contains 4898 females and 3224 males, with information on both employment and problem drinking. To eliminate the bias that may result from single‐equation estimation, we used a bivariate probit model to control for possible correlation in the unobservable factors that affect both problem drinking and employment. We find no significant negative association between problem drinking and employment for both men and women, controlling for other covariates. The findings are consistent with other research and highlight several methodological issues. Furthermore, the study suggests that estimates of the costs of problem drinking may be overstated owing to misleading labour supply relationships. Copyright © 2001 John Wiley & Sons, Ltd.
Family health effects: complements or substitutes
Authors: Ganz Michael Lee
Published: August 2002

Genetic endowments play a fundamental role in the production of health. At birth individuals have different capacities to be healthy, largely due to genetic dispositions. Whether or not individuals realize this health depends on their choice of health behaviours. Previous research has linked negative factors beyond the individual's control, which include genetic endowments, to both poor health and poor health behaviours. The health economics literature proposes that behaviours and genetic (or family health) endowments can be either substitutes or complements in the production of health. The goal of this paper is to investigate the behavioural consequences of changes in knowledge about one's genetic endowment. Using two waves of the National Health and Nutrition Examination Survey I Epidemiologic Followup Study, I find that for smokers, smoking intensity substitutes for newly diagnosed smoking‐related family cancers, while smoking intensity is complementary to newly diagnosed non‐smoking‐related family cancers. I find no evidence for the hypothesized relationships with respect to alcohol consumption among drinkers. These results have implications for the growing field of genetic testing and test development. These results also reinforce current practices of ascertaining family health histories in the context of medical history taking. Copyright © 2001 John Wiley & Sons, Ltd.
The effect of health on acute care supplemental insurance ownership: an empirical analysis
Authors: Shmueli Amir
Published: August 2002

The empirical effect of health status on private insurance ownership is a mixture of the effect of health on the demand for insurance (subjected to adverse selection) and its effect on the insurer's underwriting practice (subjected to risk‐selection). Using bivariate partial observability probit models, this paper provides an empirical identification of health effects on the probability of application and on the probability of rejection in the Israeli market for acute care supplemental health insurance. The analysis shows that while the reduced‐form health effect on ownership is negligible, the structural effects are sizeable and indicate that sicker individuals are more likely to apply, but are also more likely to be rejected. The policy implications of the above findings are discussed in the context of the Israeli health system. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of exogenous thyroid‐stimulating hormone on thyroid papillary carcinoma cells in tissue culture
Authors: Chaimoff Moshe , Raiter Annat , Avidan Sally , Shpitzer Thomas , Feinmesser Rafael , Hardy Britta
Published: August 2002

Background

To determine the prognostic value of thyroid suppression therapy in patients with thyroid carcinoma, we studied the effect of thyroid‐stimulating hormone (TSH) on the morphology, proliferation rate, and the T3, T4 production rate of primary thyroid carcinoma cells in culture.

Methods

From August 1997 to February 1998 tissues were collected for immediate culture from 13 patients undergoing surgery for thyroid cancer. Cells were incubated for 48 h with TSH in different concentrations. T3 and T4 production was measured by radioimmunoassay; cell proliferation was measured in a radioactive counter. Morphology was determined by cytologic examination.

Results

Ten samples were eligible for analysis. Changes in TSH affected T3 and T4 levels. The proliferation rate was not influenced by TSH levels.

Conclusions

Thyroid papillary carcinoma cells grown in culture maintain their T3 and T4 synthesis ability. This ability is TSH‐dependent and correlates with TSH concentration. The morphology of the cells is also maintained. However, their proliferation is not TSH‐dependent, placing the current postthyroidectomy treatment policy in question. © 2001 John Wiley & Sons, Inc. Head Neck 23: 479–483, 2001
Experimental study and analysis of the application of ice‐storage capsules in an air conditioning system
Authors: Ye Shuiquan , Ye Zhaofa , Zhu Hua , Feng Toqing , Zhang Zhanwang , Yuan Hai , Hu Shing‐Bun
Published: August 2002

Ice‐storage capsules are used in an energy‐efficient air conditioning system. Experiments and numerical simulations were conducted to investigate the effects of different structural configurations of the capsules on the freezing and melting processes of the refrigerant solution sealed inside the capsules. The predictions of the numerical simulation are in good agreement with the test results. The results show that the freezing speed of the capsules equipped with a metal core is 30% to 50% faster than for capsules without the metal core. In addition, it was found that the special refrigerant solution used in the experiment had a lower freezing point and a higher freezing speed than water. The effects of the size of the metal core, and the coolant temperatures are also investigated. © 2001 Scripta Technica, Heat Trans Asian Res, 31(1): 21–27, 2002
Characteristics of particle mixtures in a liquid‐fluidized bed
Authors: Hashizume Kenichi , Matsue Takahiro
Published: August 2002

Behavior of particle mixtures was investigated in a liquid‐fluidized bed experimentally. In the experiment, two kinds of particles of different diameters, and of the same or different materials, were charged in a fluidization column and fluidized by water. Based on the observation of fluidization, a flow pattern map was proposed using the Archimedes number ratio and the terminal velocity ratio, which classifies the two patterns, that is, separation and homogeneous mix. Measured mean void fractions of particle mixtures agreed well with the values calculated from those for each particle independently. © 2001 Scripta Technica, Heat Trans Asian Res, 30(3): 175–184, 2001
Simulation of willow short‐rotation forest evaporation using a modified Shuttleworth–Wallace approach
Authors: Iritz Z. , Tourula T. , Lindroth A. , Heikinheimo M.
Published: August 2002

Evaporation from a willow short‐rotation forest was analysed using a modified version of the Shuttleworth–Wallace model. The main modification consisted of a two‐layer soil module, which enabled soil surface resistance to be calculated as a function of the wetness of the top soil. Introduction of the threshold value of the leaf area index when scaling up from the leaf to the canopy resistance resulted in improvement to the simulated evaporation. The analysis was concentrated mainly on the 1988 season (May–October) when total evaporation was measured by the energy balance/Bowen ratio method throughout the growing season, covering all stages of canopy development. At the beginning of the 1994 season, soil evaporation were also measured with a ventilated chamber system. The general seasonal dynamics of the evaporation were fairly well simulated with the model. The largest deviation between measured and simulated evaporation occurred in June, when the model underestimated evaporation by about 1 mm day−1. The model underestimated also in May but not as much as in June. In September and October the performance of the model was very good. For 130 days of the period May–October the cumulated measured evaporation was 364 mm and the simulated evaporation for the same days was 362 mm. It should be pointed out that this result was obtained without calibrating the model against the measured evaporation. The total simulated evaporation for the season was 450 mm with transpiration constituting 298 mm (66%), soil evaporation 102 mm (23%) and interception evaporation 50 mm (11%). The sensitivity analysis showed, in general, that simulated evaporation was most sensitive to changes in resistances when the leaf area index was smallest, i.e. under non‐closed canopy conditions. Changes in stomatal resistance, which is one of the most sensitive parameters, with associated changes in canopy transpiration, resulted in a negative feedback effect on soil evaporation. This reduced the total evaporation's sensitivity to stomatal resistance. This type of interaction between canopy and soil or undergrowth fluxes has been observed in other studies as well. Copyright © 2001 John Wiley & Sons, Ltd.
Spatial patterns of suspended sediment yields in a humid tropical watershed in Costa Rica
Authors: Krishnaswamy Jagdish , Richter Daniel D. , Halpin Patrick N. , Hofmockel Michael S.
Published: August 2002

An Erratum has been published for this article in Hydrological Processes 16(5) 2002, 1130–1131.

Humid tropical regions are often characterized by extreme variability of fluvial processes. The Rio Terraba drains the largest river basin, covering 4767 km2, in Costa Rica. Mean annual rainfall is 3139±419sd mm and mean annual discharge is 2168±492sd mm (1971–88). Loss of forest cover, high rainfall erosivity and geomorphologic instability all have led to considerable degradation of soil and water resources at local to basin scales. Parametric and non‐parametric statistical methods were used to estimate sediment yields.

In the Terraba basin, sediment yields per unit area increase from the headwaters to the basin mouth, and the trend is generally robust towards choice of methods (parametric and LOESS) used. This is in contrast to a general view that deposition typically exceeds sediment delivery with increase in basin size. The specific sediment yield increases from 112±11·4sd t km−2 year−1 (at 317·9 km2 on a major headwater tributary) to 404±141·7sd t km−2 year−1 (at 4766·7 km2) at the basin mouth (1971–92). The analyses of relationships between sediment yields and basin parameters for the Terraba sub‐basins and for a total of 29 basins all over Costa Rica indicate a strong land use effect related to intensive agriculture besides hydro‐climatology. The best explanation for the observed pattern in the Terraba basin is a combined spatial pattern of land use and rainfall erosivity. These were integrated in a soil erosion index that is related to the observed patterns of sediment yield. Estimated sediment delivery ratios increase with basin area. Intensive agriculture in lower‐lying alluvial fans exposed to highly erosive rainfall contributes a large part of the sediment load. The higher elevation regions, although steep in slope, largely remain under forest, pasture, or tree‐crops. High rainfall erosivity (>7400 MJ mm ha−1 h−1 year −1) is associated with land uses that provide inadequate soil protection. It is also associated with steep, unstable slopes near the basin mouth.

Improvements in land use and soil management in the lower‐lying regions exposed to highly erosive rainfall are recommended, and are especially important to basins in which sediment delivery ratio increases downstream with increasing basin area. Copyright © 2001 John Wiley & Sons, Ltd.
Concurrent overexpression of ETS‐1 and C‐met correlates with a phenotype of high cellular motility in human esophageal cancer
Authors: Saeki Hiroshi , Oda Shinya , Kawaguchi Hidetoshi , Ohno Shinji , Kuwano Hiroyuki , Maehara Yoshihiko , Sugimachi Keizo
Published: August 2002

Hepatocyte growth factor (HGF) stimulates cell motility as well as mitotic activity of cells. High concentrations of HGF or overexpression of its cellular receptor c‐Met in cancer have been reported. We analyzed the expression status of c‐Met immunohistochemically in 76 cases of human esophageal cancer. Overexpression of c‐Met was noted at a considerably high frequency. Intriguingly, c‐Met overexpression was frequent in a specific type of cell nest formation in tumors, i.e., the small nest type, in which tumors form small, dispersed cell nests. Further immunohistochemical analyses using serial sections revealed a striking coincidence between overexpression of c‐Met and its transcriptional factor, Ets‐1. Overexpression of c‐Met and Ets‐1 was statistically more frequent in small nest type tumors. The close correlation in expression status between Ets‐1 and c‐Met was also confirmed using 6 established human esophageal cancer cell lines. In addition, cells that expressed high levels of Ets‐1 and c‐Met exhibited an extremely motile phenotype by HGF stimulation in vitro. The presence of HGF in tissue sections was confirmed using similar immunohistochemical approaches. These observations suggest that in human esophageal cancer cells the transcriptional factor Ets‐1 upregulates the expression of c‐Met and, consequently, confers on cells a highly motile phenotype leading to a specific form of tumor development. © 2001 Wiley‐Liss, Inc.
In situ repair of cyclobutane pyrimidine dimers in skin and melanocytic nevi of cutaneous melanoma patients
Authors: Zhao Chunyan , Snellman Erna , Jansen Christer T. , Hemminki Kari
Published: August 2002

The development of cutaneous malignant melanoma (CMM) and its precursor lesions, melanocytic nevi, has been linked to sun exposure. Cyclobutane pyrimidine dimers (CPDs) are the majority of DNA lesions induced by sun exposure. In our study, we investigated if CMM patients have impaired ability to repair CPDs in skin as well as in melanocytic nevi. The repair kinetics were followed up to 3 weeks after exposure to 40 mJ/cm2 of solar simulating radiation. Altogether 12 CMM patients and 10 healthy controls were included in our study. Buttock skin biopsies were taken at 0 hr, 48 hr and 3 weeks after UV exposure, whereas melanocytic nevi and surrounding skin biopsies were taken only at 0 hr and 3 weeks. The CPD levels were measured by a 32P‐postlabeling method. The results showed that the repair rate of CPDs in neither the skin nor the nevi was significantly different between the CMM patients and the control group. For both groups, the repair rate of TT = C was faster than that for TT = T. The important finding is that about 10% of the initial TT = T damage remained unrepaired after 3 weeks, and was detectable in normal epidermis as well as in nevi of all subjects. We also found that the amount of TT = C and TT = T at 0 hr in nevi was significantly lower than that in surrounding skin (Wilcoxon rank sum test, p < 0.05). © 2002 Wiley‐Liss, Inc.
Assessment of genomic instability in breast cancer and uveal melanoma by random amplified polymorphic DNA analysis
Authors: Papadopoulos Sarantos , Benter Thomas , Anastassiou Gerasimos , Pape Michael , Gerhard Schaller , Bornfeld Norbert , Ludwig Wolf‐Dieter , Dörken Bernd
Published: August 2002

Some types of cancer have been associated with abnormal DNA fingerprinting. We used random amplified polymorphic DNA (RAPD) to generate fingerprints that detect genomic alterations in human breast cancer. Primers were designed by choosing sequences involved in the development of DNA mutations. Seventeen primers in 44 different combinations were used to screen a total of 6 breast cancer DNA/normal DNA pairs and 6 uveal melanoma DNA/normal DNA pairs. Forty‐five percent of these combinations reliably detected quantitative differences in the breast cancer pairs, while only 18% of these combinations detected differences in the uveal melanoma pairs. Fourteen (32%) and 12 (27%) primers generated a smear or did not produce any band patterns in the first and second cases, respectively. Taking into account the ability of RAPD to screen the whole genome, our results suggest that the genomic damage in breast cancer is significantly higher than in uveal melanoma. Our study confirms other reports that the molecular karyotypes produced with random priming, called amplotypes, are very useful for assessing genomic damage in cancer. © 2002 Wiley‐Liss, Inc.
Protease inhibitors restore radiation‐induced apoptosis to Bcl‐2‐expressing lymphoma cells
Authors: Kurland John F. , Meyn Raymond E.
Published: August 2002

The proteasome pathway is important for the turnover of many regulatory proteins. This pathway has recently become a target for antitumor agents and several research groups have demonstrated that inhibitors with specificities for the proteasome are potent apoptosis‐inducing agents. Many mechanisms by which proteasome inhibitors exert their effects have been suggested, including inhibition of NF‐κB activity and stabilization of the p53 tumor suppressor protein. We investigated the ability of inhibitors with specificities for the proteasome and for another protein degradation enzyme, calpain, to sensitize a murine B‐cell lymphoma with constitutive NF‐κB1 homodimer activity and high expression of Bcl‐2 protein to radiation‐induced apoptosis. Protease inhibitors tested were calpain inhibitor I, calpain inhibitor II, calpeptin, MG132, and Lactacystin. All five inhibitors induced apoptosis and sensitized cells to radiation despite the maintenance of Bcl‐2 protein levels throughout the course of treatment. An electrophoretic migration shift assay for NF‐κB1 activity provided evidence that reversal of NF‐κB activity was not required for induction of cell death; however, p53 levels were elevated for all inhibitors tested. HL‐60 cells, devoid of p53, could not be sensitized to radiation by MG132 treatment, suggesting that p53 was important for cell death induced by combined treatment with protease inhibitors and radiation. We concluded that protease inhibitors are capable of overcoming the protective effects of Bcl‐2 to induce apoptosis and suggest that protease inhibitor treatment, when combined with ionizing radiation, leads to p53‐mediated apoptosis. © 2001 Wiley‐Liss, Inc.
Mitotic arrest induced by XK469, a novel antitumor agent, is correlated with the inhibition of cyclin B1 ubiquitination
Authors: Lin Hong , Liu Xiang Y. , Subramanian Balanehru , Nakeff Alexander , Valeriote Fred , Chen Ben D.
Published: August 2002

XK469 (NSC 697887) is a novel antitumor agent with broad activity against a variety of tumors. Previous studies suggest that XK469 is a topoisomerase IIβ poison with functional activity similar to that of 4′‐(9‐acridinylamino) methanesulfon‐m‐anisidide (m‐AMSA). The goal of our study was to investigate its mechanism of action further using a human HCT‐116 (H116) colon tumor cell model. Concentration‐survival curves with continuous exposure indicated that XK469 had low cytotoxic activity against H116 cells. Cell cycle analysis revealed that XK469 is a phase‐specific cell cycle blocker that is associated with increased levels of cyclin B1, cyclin A and p53 but not CDK1 (cdc2) or cyclin E. In contrast, treatment of H116 cells with m‐AMSA caused a total degradation of both cyclin A and B1 but enhanced expression of cyclin E and p53. Accumulation of cyclin B1 in XK469‐treated cells was correlated with the inhibition of cyclin B1 ubiquitination, a metabolic process mandatory for proteasome‐mediated protein turnover. However, no inhibition of cyclin B1 ubiquitination was detected in cells treated with m‐AMSA or colchicine, a known mitotic inhibitor. Furthermore, unlike m‐AMSA, XK469 did not induce caspase activation or apoptotic cell death in H116 cells. Our results suggest that XK469 is a phase‐specific cell cycle inhibitor with a unique mechanism of action that is correlated with the inhibition of cyclin B1 ubiquitination and its accumulation at early M phase. © 2002 Wiley‐Liss, Inc.
Combined gemcitabine and radioimmunotherapy for the treatment of pancreatic cancer
Authors: Cardillo Thomas M. , Blumenthal Rosalyn , Ying Zhiliang , Gold David V.
Published: August 2002

MAb‐PAM4 is an anti‐MUC1 antibody that has been shown to be reactive with 85% of pancreatic adenocarcinomas with no reactivity with normal pancreas or other tissues. Initial clinical studies have shown excellent targeting with high tumor/nontumor ratios. Gemcitabine, an analog of deoxycytidine, is currently a frontline treatment for pancreatic cancer. Acting via a number of metabolic pathways, gemcitabine is also a powerful radiosensitizer. Combined‐modality, chemo/radiosensitization with gemcitabine and low dose 131I‐PAM4 radioimmunotherapy was performed to determine if a more effective treatment procedure could be developed. Athymic nude mice bearing large (1 cm3) CaPan1 human pancreatic tumors were given a single treatment cycle consisting of gemcitabine, 333 mg/m2 administered on Days 0, 3, 6, 9 and 12 by intraperitoneal injection, along with either 100 or 200 μCi, 131I‐PAM4 administered on Day 0 by intravenous injection. Gemcitabine did not interfere with the biodistribution of radiolabeled antibody. Specific tumor targeting was observed for 131I‐PAM4, with a tumor/blood radiation dose ratio of 2.6 over the first 14 days. Gemcitabine alone and low dose radioimmunotherapy alone, each had no affect upon tumor growth; no statistical differences were noted in comparison to the untreated group. When combined, however, a statistically significant (p = 0.0324), synergistic anti‐tumor effect was observed. Median survival time doubled for the combined treatment regimen compared to single modality treatment groups. The combined treatment modality was well tolerated by the mice. Our data show that combined gemcitabine with radioimmunotherapy may provide an improved alternative for the treatment of pancreatic cancer, achieving successful anti‐tumor effects with low toxicity. © 2001 Wiley‐Liss, Inc.
Debt management in Brazil: evaluation of the real plan and challenges ahead
Authors: Bevilaqua Afonso S. , Garcia Márcio G.P.
Published: August 2002

The Brazilian domestic debt has posed two challenges to policy‐makers: it has grown very fast and its maturity is extremely short. This has prompted fears that a default or a compulsory lengthening scheme would be imposed. Here, we analyse the domestic public debt management experience in Brazil, searching for policy prescriptions for the next few years. After briefly reviewing the recent domestic public debt history, we decompose the large rise in federal bonded debt during 1995–2000, searching for its macroeconomic causes. The main culprits are the extremely high interest payments—which, until 1998, were caused by the weak fiscal stance and the quasi‐fixed exchange‐rate regime; and since 1999, by the impact of the currency depreciation on the dollar‐indexed and the external debt—, and the accumulation of assets of doubtful value, much of which may have to be written off in the future. Simulation exercises of the net debt path for the near future underscore the importance of a tighter fiscal stance to prevent the debt‐GDP ratio from growing further. Given the need to quickly lengthen the debt maturity, our main policy advice is to foster, and rely more on, inflation‐linked bonds. Copyright © 2002 John Wiley & Sons, Ltd.
Mother–infant communication can be enhanced after conception by in‐vitro fertilization
Authors: Papaligoura Zaira , Trevarthen Colwyn
Published: August 2002

To determine if stress associated with artificial pregnancy treatment might affect early communication, video microanalysis was applied to examine face‐to‐face play between infants and their mothers in the first 5 months. Three groups of infants participated: 8 born after in‐vitro fertilization (IVF) treatment employing parental gametes; 8 born after standard infertility treatment (INF), which did not include IVF; and 8 infants whose parents had experienced no infertility problems (Control group: C). All were videotaped at home in free play with their mothers at 4, 7, 13, and 21 weeks of age. A 3‐min extract of each video was reviewed in detail by means of an objective coding system, to define the style of communication. Data from this analysis was subjected to two separate repeated measures of analyses of variance.

We found no evidence of detrimental effects of infertility treatment on mother–infant communication, but there were “positive” differences in behavior in the pairs where the mother had been so treated. Thus, while maternal “caretaking” episodes had become infrequent in the control group by the age of 21 weeks, in the two treatment groups the mothers continued to show many caretaking behaviors with infants of this age. Furthermore, infants of both the IVF and INF groups showed significantly higher frequencies of “play” episodes than those in the control group (p = 0.018 and p = 0.004, respectively). Apart from these differences, mother–infant interactions were generally the same in the three groups.

The results indicate that communication between mothers and infants is likely to develop along the normal path after IVF or INF treatment, but that mothers who have had these infertility treatments may be more attentive to their infants, and their infants are significantly more playful. Since the IVF and the INF groups were similar, it would appear that these differences from the control group are related to the experience of a successful treatment for infertility, and not related to any particular stresses that may be associated with IVF treatment. ©2001 Michigan Association for Infant Mental Health.
Organizational Learning and the Case for Knowledge‐Based Systems
Authors: Petrides Lisa A.
Published: August 2002

This chapter discusses organizational learning and the required reassessment and redesign of internal structures and procedures related to the flow of information throughout the organization. It provides a framework for the integration of institutional research within the larger context of organizational learning and the creation and maintenance of a research culture facilitated by knowledge management.
Composites consisting of poly(methyl methacrylate) and alumina powder: An evaluation of their mechanical and biological properties
Authors: Shinzato Shuichi , Nakamura Takashi , Kokubo Tadashi , Kitamura Yoshiro
Published: August 2002

We developed new composites consisting of comparatively high molecular weight poly(methyl methacrylate) (hPMMA) and δ‐alumina powder or α‐alumina powder (designated δ‐APC and α‐APC, respectively) that allowed direct bone formation on their surfaces in vivo. δ‐Alumina powder was manufactured by the fusing and quenching of pulverized alumina powder. It was composed mainly of δ‐crystal phases of alumina. The purpose of this study was to evaluate the static mechanical properties and biological properties of these composites. The hPMMA itself was used as a reference material. The bending strength and Young's modulus of both δ‐APC and α‐APC were significantly higher than those of hPMMA, and the alumina composites are believed to be strong enough for use under weight‐bearing conditions. The three types of composites were packed into the intramedullary canals of rat tibiae to evaluate osteoconductivity, as determined by an affinity index. Rats were sacrificed 4 and 8 weeks after surgery. The affinity index, equal to the length of bone in direct contact with the composite surface and expressed as a percentage of the total length of the composite surface, was calculated for each composite at each interval. Histologically, new bone had formed along the surfaces of both δ‐APC and α‐APC within 4 weeks. The affinity indices for both δ‐APC and α‐APC increased significantly with time up to 8 weeks. At 8 weeks, the affinity index for δ‐APC was significantly higher than the indices for α‐APC and hPMMA. This study revealed that the excellent osteoconductivity of δ‐APC was due to the δ‐crystal phases of alumina and the high molecular weight of hPMMA. δ‐APC shows promise as a base for developing a highly osteoconductive and mechanically strong biomaterial. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 585–591, 2002
Membrane‐encased polymer millirods for sustained release of 5‐fluorouracil
Authors: Qian Feng , Nasongkla Norased , Gao Jinming
Published: August 2002

This article describes the design and development of a novel membrane‐encased polymer millirod for the sustained release of an anticancer drug, 5‐fluorouracil (5‐FU). The millirod consists of two functional compartments: (1) an inner 5‐FU‐loaded monolithic millirod as the drug depot, and (2) an outer NaCl‐impregnated polymer membrane to control the release rate of 5‐FU. The inner millirod is fabricated by a compression‐heat molding procedure to permit the entrapment of 5‐FU particles in the poly(D,L‐lactide‐co‐glycolide) (PLGA) matrix. The drug loading density is controlled at 30 w/w% to achieve a burst release of 5‐FU (>90% of the drug are released within 48 h) from the monolithic millirod. The NaCl‐impregnated PLGA membrane is generated by solvent casting and is then wrapped over the monolithic millirod to produce the membrane‐encased millirod. Scanning electron microscopy shows that dissolution of NaCl particles produces a semipermeable polymer membrane to provide a sustained release of 5‐FU. The membrane thickness and the density of NaCl particles inside the membrane are useful parameters to control the release kinetics of 5‐FU. Under the experimental conditions in this study, sustained release of 5‐FU [rates between 0.1 and 0.4 mg/(day · cm of millirod)] is achieved for 2 to 5 weeks in phosphate‐buffered saline (pH 7.4) at 37°C. Results from this study demonstrate that membrane‐encased polymer millirods provide controllable sustained release kinetics for applications in intratumoral drug delivery. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 203–211, 2002
Effect of water vapor treatment on apatite formation on precalcified titanium and bond strength of coatings to substrates
Authors: Feng B. , Chen Y. , Zhang X.D.
Published: August 2002

In previous investigations, a simple method, precalcification, was developed for bioactivating titanium. After a titanium sample was precalcified in a boiling saturated Ca(OH)2 solution and then immersed in a calcium phosphate supersaturated solution, an apatite coating rapidly precipitated onto its surface. In the present study, heat‐treatment in water vapor was carried out prior to precalcification. Heat‐treatment in water vapor stimulated the chemical reaction between titanium, calcium, and phosphate. Coating properties were improved, and the bond strength of the coating to substrate was enhanced. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 12–17, 2002
Enzymatic responses of human deciduous pulpal fibroblasts to dental restorative materials
Authors: Chen Chern‐Chin , Chen Robert Cheng‐Shen , Huang Shun‐Te
Published: August 2002

The purpose of this study was to evaluate the responses of succinic dehydrogenase (SDH) and alkaline phosphatase (ALP) activities of human deciduous teeth pulpal fibroblasts (HDPF) to dental restorative materials. Tested materials included Z100 (3M), Dyract (Dentsply), FujiII (GC), and FujiIILC (GC). IRM (Dentsply) and culture medium (MD) alone were used as positive and negative controls, respectively. Specimens 6 mm (diameter) × 3 mm were prepared in accordance with manufacturers’ instructions. For light‐cured materials, specimens were light cured for 40 s on both sides under a celluloid strip. For chemical‐cured materials, specimens were allowed to set at room temperature for 15 min. The specimens were immersed in 1 mL of culture medium without serum for 24 h at room temperature. The extracts were filtered through 0.22‐mm filters. HDPF (10,000 cells/well) was incubated with 100 μL of extract and 20 % FBS in a 96‐well plate for 24 h in a 37°, 5 % CO2 incubator. Six wells per material were prepared. Optical density (OD) of SDH and ALP of HDPF were measured by a spectrophotometer. The means were analyzed by ANOVA and then a Duncan Test. The ranking of OD of SDH was IRM < FujiIILC < FujiII = Z100 < Dyract < MD (p < 0.05). The ranking of OD of ALP was IRM < Z100 = Dyract < FujiII < FujiIILC < MD (p < 0.05). The result showed that all of the tested restorative materials were cytotoxic to human deciduous pulpal fibroblasts. The cytotoxicity of resin‐modified glass ionomer cements (FujiIILC) was stronger than that of traditional glass ionomer cements (FujiII) and composite resin (Z100), and that of compomer (Dyract) was the weakest. On the contrary, ALP activities of resin‐modified glass ionomer cements (FujiIILC) and composite resin (Z100) were higher than those of traditional glass ionomer cements (FujiII), while those of compomer (Dyract) were the lowest. It is concluded that, in this study, FujiIILC was the most cytotoxic material and the least inhibitive of ALP activities, Dyract was the weakest cytotoxic material and had the highest inhibition of ALP activities. The rankings of the MTT assay and the ALP assay were not consistent. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 452–457, 2002; DOI 10.1002/jbm.1291
ATP stimulates human placental 11β‐hydroxysteroid dehydrogenase type 2 activity by a novel mechanism independent of phosphorylation
Authors: Yang K. , Hardy D.B. , Doumouras M.A. , van Beek J.P. , Rocha E.
Published: August 2002

The human placental 11β‐hydroxysteroid dehydrogenase type 2 (11β‐HSD2) is believed to play a key role in fetal development since this enzyme protects the fetus from exposure to high levels of maternal cortisol by virtue of converting maternal cortisol to its inert metabolite cortisone. The present study was undertaken to examine the effect of ATP on 11β‐HSD2 activity in human placental microsomes. Enzyme activity, reflected by the rate of conversion of cortisol to cortisone, was stimulated more than six‐fold by 0.5 mM ATP (EC50 = 0.2 mM). Such stimulation appears to be mediated through a novel mechanism independent of ATP‐induced phosphorylation of the reaction components since AMP‐PNP, a non‐hydrolyzable analogue of ATP, was equally effective. The ATP‐induced stimulation of 11β‐HSD2 activity is adenine nucleotide specific in that a similar stimulation was observed with ADP and AMP but not with CTP, GTP, or UTP. Furthermore, ATP increased the maximal velocity (Vmax) of the 11β‐HSD2 catalyzed conversion of cortisol to cortisone without altering the apparent Km of 11β‐HSD2 for cortisol, suggesting that ATP may stimulate enzyme activity by interacting with the enzyme at a site other than that involved in substrate binding. In conclusion, the present study has identified ATP as a novel regulator of human placental 11β‐HSD2 in vitro. It is conceivable that intracellular ATP may have a profound effect on 11β‐HSD2 function in vivo. J. Cell. Biochem. 84: 295–300, 2002. © 2001 Wiley‐Liss, Inc.
Regulation of tumor invasion and metastasis in protein kinase C epsilon‐transformed NIH3T3 fibroblasts
Authors: Tachado Souvenir D. , Mayhew Mark W. , Wescott Ginger G. , Foreman Tonia L. , Goodwin Crystal D. , McJilton Meagan A. , Terrian David M.
Published: August 2002

Protein kinase C epsilon is an oncogenic, actin nucleating protein that coordinately regulates changes in cell growth and shape. Cells constitutively expressing PKCϵ spontaneously acquire a polarized morphology and extend long cellular membrane protrusions. Here we report that the regulatory C1 domain of PKCϵ contains an actin binding site that is essential for the formation of elongate invadopodial‐like structures, increased pericellular metalloproteinase activity, in vitro invasion of a Matrigel barrier, and the invasion and metastasis of tumors grown in vivo by PKCϵ‐transformed NIH3T3 fibroblasts in nude mice. While removing this small actin binding motif caused a dramatic reversion of tumor invasion, the deletion mutant of PKCϵ remained oncogenic and tumorigenic in this experimental system. We propose that PKCϵ directly interacts with actin to stimulate polymerization and the extension of membrane protrusions that transformed NIH3T3 cells use in vivo to penetrate and degrade surrounding tissue boundaries. J. Cell. Biochem. 85: 785–797, 2002. © 2002 Wiley‐Liss, Inc.
Vanadate protects human neuroblastoma SH‐SY5Y cells against peroxynitrite‐induced cell death
Authors: Saeki Makio , Maeda Sadaaki , Kamisaki Yoshinori
Published: August 2002

We investigated the effect of vanadate, a tyrosine phosphatase inhibitor, on cell death induced by peroxynitrite in human neuroblastoma SH‐SY5Y cells. Vanadate prevented cell death induced by 3‐morpholinosydnonimine (SIN‐1), a peroxynitrite donor; whereas SIN‐1‐induced cell death was not prevented by neither okadaic acid, an inhibitor of serine/threonine phosphatases 1 and 2A, nor cyclosporin A, an inhibitor of serine/threonine phosphatase 2B. Vanadate did not prevent cell death induced by N‐ethyl‐2‐(1‐ethyl‐hydroxy‐2‐nitrosohydrazino)‐ethanamine, a nitric oxide donor. Wortmannin, an inhibitor of phosphatidylinositol 3‐kinase (PI3‐kinase), did not block the protective effect of vanadate, suggesting that the protective effect of vanadate is independent on PI3‐kinase. Vanadate increased tyrosine phosphorylation of several proteins including the focal adhesion protein p130 Crk‐associated substrate (p130cas). By the treatment with SIN‐1, the endogenous association of p130cas and Crk was disrupted, and the association was restored by vanadate treatment. These results suggest that disruption of tyrosine phosphorylation signaling may be critical for peroxynitrite‐induced cell death, and that vanadate prevents cell death at least in part through the enhancement in tyrosine phosphorylation of the proteins including p130cas. J. Cell. Biochem. 85: 721–727, 2002. © 2002 Wiley‐Liss, Inc.
Chromatin of Trypanosoma cruzi: In situ analysis revealed its unusual structure and nuclear organization
Authors: Spadiliero Barbara , Nicolini Claudio , Mascetti Giancarlo , Henríquez Diana , Vergani Laura
Published: August 2002

Chromatin of Trypanosoma cruzi is known to be organized in classical nucleosomal filaments, but surprisingly, these filaments do not fold in visible chromosomes and the nuclear envelope is preserved during cell division. Our hypothesis about the role of chromatin structure in regulating gene expression and, more generally, cell functioning, pressed us to verify if chromatin organization is modulated during the parasite life‐cycle. To this end, we analyzed in situ the fine structural organization of T. cruzi chromatin by means of an integrated biophysical approach, using differential scanning calorimetry and fluorescence microscopy. We observed that logarithmic forms exhibit a less condensed chromatin with respect to the stationary ones. Thermal analysis revealed that parasite chromatin is organized in three main levels of condensation, barring from the polynucleosomal filament till to superstructured fibers. Besides, the fluorescence images of nuclei showed a characteristic chromatin distribution, with defined domains localized near to the nuclear envelope. While in stationary parasites, these regions are highly condensed, in logarithmic forms they unfold by extending themselves toward the center of nucleus. These observations suggest that, in comparison with higher eukaryotes, in T. cruzi the nuclear envelope plays an unusual and pivotal role in interphase and in mitosis. J. Cell. Biochem. 85: 798–808, 2002. © 2002 Wiley‐Liss, Inc.
Structural and functional studies on Troponin I and Troponin C interactions
Authors: Ngai Sai‐Ming , Hodges Robert S.
Published: August 2002

Troponin I (TnI) peptides (TnI inhibitory peptide residues 104–115, Ip; TnI regulatory peptide resides 1–30, TnI1–30), recombinant Troponin C (TnC) and Troponin I mutants were used to study the structural and functional relationship between TnI and TnC. Our results reveal that an intact central D/E helix in TnC is required to maintain the ability of TnC to release the TnI inhibition of the acto‐S1‐TM ATPase activity. Ca2+‐titration of the TnC‐TnI1–30 complex was monitored by circular dichroism. The results show that binding of TnI1–30 to TnC caused a three‐folded increase in Ca2+ affinity in the high affinity sites (III and IV) of TnC. Gel electrophoresis and high performance liquid chromatography (HPLC) studies demonstrate that the sequences of the N‐ and C‐terminal regions of TnI interact in an anti‐parellel fashion with the corresponding N‐ and C‐domain of TnC. Our results also indicate that the N‐ and C‐terminal domains of TnI which flank the TnI inhibitory region (residues 104 to 115) play a vital role in modulating the Ca2+‐ sensitive release of the TnI inhibitory region by TnC within the muscle filament. A modified schematic diagram of the TnC/TnI interaction is proposed. © 2001 Wiley‐Liss, Inc.
Transcriptional activation of rat creatine kinase B by 17β‐estradiol in MCF‐7 cells involves an estrogen responsive element and GC‐rich sites
Authors: Wang Fan , Samudio Ismael , Safe Stephen
Published: August 2002

The rat creatine kinase B (CKB) gene is induced by estrogen in the uterus, and constructs containing rat CKB gene promoter inserts are highly estrogen‐responsive in cell culture. Analysis of the upstream −568 to −523 region of the promoter in HeLa cells has identified an imperfect palindromic estrogen response element (ERE) that is required for hormone inducibility. Analysis of the CKB gene promoter in MCF‐7 breast cancer cells confirmed that pCKB7 (containing the −568 to −523 promoter insert) was estrogen‐responsive in transient transfection studies. However, mutation and deletion analysis of this region of the promoter showed that two GC‐rich sites and the concensus ERE were functional cis‐elements that bound estrogen receptor α (ERα)/Sp1 and ERα proteins, respectively. The role of these elements was confirmed in gel mobility shift and chromatin immunoprecipitation assays and transfection studies in MDA‐MB‐231 and Schneider Drosophila SL‐2 cells. These results show that transcriptional activation of CKB by estrogen is dependent, in part, on ERα/Sp1 action which is cell context‐dependent. J. Cell. Biochem. 84: 156–172, 2002. © 2001 Wiley‐Liss, Inc.
Transition state docking: A probe for noncovalent catalysis in biological systems. Application to antibody‐catalyzed ester hydrolysis
Authors: Tantillo Dean J. , Houk K. N.
Published: August 2002

A strategy for pinpointing favorable noncovalent interactions between transition states and active sites of biological catalysts is described. This strategy combines high‐level quantum mechanical calculations of transition state geometries with an automated docking procedure using AutoDock. By applying this methodology to antibody‐catalyzed hydrolyses of aryl esters (by the 48G7, CNJ206, and 17E8 families of antibodies), varying levels of catalysis are explained in terms of specific hydrogen bonding interactions between combining site residues and transition states. Although these families of antibodies were produced in separate experiments by different researchers using related but different haptens, the mechanism of transition state stabilization appears to be highly conserved. Despite being elicited in response to anionic phosphonate haptens, the best catalysts often utilize hydrogen bond acceptors to stabilize transition states. A mutant of antibody CNJ206, designed based on this observation and predicted to be a better catalyst, is proposed. In the case of antibody 48G7, affinity maturation is shown to produce a catalyst that is highly selective for one of two enantiomeric transition states from a nonselective germline precursor. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 84–95, 2002
Calculation of X‐ray scattering intensities by means of the coupled cluster singles and doubles model
Authors: Watanabe Noboru , Kamata Yohei , Yamauchi Kota , Udagawa Yasuo
Published: August 2002

Total X‐ray scattering intensity σee(q) is very sensitive to electron correlation effects. In this study σee(q) of N2, CO, and N2O have been computed by the coupled cluster singles and doubles (CCSD) method and compared with configuration interaction singles and doubles (CISD) calculations as well as experimental observations. σee(q) curves by CCSD calculations are rather close to those by CISD, but although small, there still exist some discrepancies between calculated and observed values. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1315–1320, 2001
Bounds on affine caps
Authors: Bierbrauer Jürgen , Edel Yves
Published: August 2002

We present a short and elementary proof for an upper bound on caps in affine spaces. The bound generalizes and strengthens a result by Meshulam. The proof is inspired by Meshulam's Fourier transform method without making explicit use of the Fourier transform. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 111–115, 2002; DOI 10.1002/jcd.10000
Phosphorylation of focal adhesion kinase (pp125FAK) is increased in human keratinocytes induced to migrate by extracellular matrices
Authors: Yurko Mary A. , O'Toole Edel A. , Woodley David T.
Published: August 2002

During the healing process of skin wounds, human keratinocytes migrate across a provisional matrix of the wound bed. The mechanisms by which keratinocytes migrate on connective tissue are not known. In this study, we examined the role of focal adhesion kinase (FAK), an 125 kDa protein that co‐localizes with focal adhesions in cells plated on extracellular matrix. We induced human keratinocytes into various states of migration by plating them on extracellular matrices that minimally, moderately, or strongly induce cellular migration, and then examined the expression of FAK at the protein level and its degree of tyrosine phosphorylation using Western immunoblotting and immunoprecipitation. In highly migratory human keratinocytes, we found that three proteins were predominantly tyrosine phosphorylated, one of them being FAK. Tyrosine phosphorylation of FAK tightly correlated with the level of cellular motility but not cell attachment to the matrix. Time course experiments demonstrated that in highly motile keratinocytes, tyrosine phosphorylation of FAK peaked at 12 h, the time when maximal migration on the matrix ensues. In contrast to FAK, the β1 integrin subunit of human keratinocytes that configures with the α2, α3, and α5 integrin subunits to form integrin receptors for matrix, did not display tyrosine phosphorylation linked to motility. Using anti‐sense oligonucleotides to FAK, we demonstrate that FAK is required for human keratinocyte migration, but not for focal adhesion formation. © 2001 Wiley‐Liss, Inc.