bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of a 7-Day Continuous Intravenous Infusion of Decitabine: Inhibition of Promoter-Specific and Global Genomic DNA Methylation
Authors: Samlowski Wolfram E. , Leachman Sancy A. , Wade Mark , Cassidy Pamela , Porter-Gill Patricia , Busby Leslie , Wheeler Richard , Boucher Kenneth , Fitzpatrick Frank , Jones David A. , Karpf Adam R.
Published: March 2005

Purpose

The nucleoside analog 5-aza-2′-deoxycytidine (5-aza-CdR, decitabine) is a potent inhibitor of DNA methylation in vitro. Cellular treatment with this agent induces the re-expression of methylation-silenced genes. It remains unclear to what extent this compound inhibits DNA methylation in vivo. A clinical study was designed to examine the molecular effects and toxicity of a continuous 1-week intravenous infusion of decitabine in solid tumor patients.

Methods

Ten patients with refractory solid tumors were included in this study. Decitabine was administered at 2 mg/m2/d via continuous infusion for 168 hours. Quantitative polymerase chain reaction and high performance liquid chromatography were utilized to measure promoter-specific and global DNA methylation in peripheral-blood cells before and after treatment.

Results

Transient grade III/IV neutropenia (two patients) and grade II thrombocytopenia (one patient) was observed at the lowest planned dose step (2 mg/m2/d for 7 days). Nonhematologic toxicities were not observed. Quantitative polymerase chain reaction demonstrated significant MAGE-1 promoter hypomethylation by 14 days after the start of treatment in all 13 treatment cycles examined. Significant genomic DNA hypomethylation was also seen by day 14 in 11 of 13 treatment cycles analyzed. Genomic DNA methylation reverted to baseline levels by 28 to 35 days after the start of treatment, demonstrating that inhibition of DNA methylation by decitabine is transient.

Conclusion

A 168-hour continuous infusion of decitabine is well tolerated and results in the inhibition of promoter-specific and genomic DNA methylation in vivo. This treatment schedule is suitable for evaluation of decitabine in combination with agents whose activity may be enhanced by the reversal of DNA methylation–mediated gene silencing.
Slow-moving predatory gastropods track prey odors in fast and turbulent flow
Authors: Ferner Matthew C. , Weissburg Marc J.
Published: March 2005

Olfactory searching by aquatic predators is reliant upon the hydrodynamic processes that transport and modify chemical signals. Previous studies indicate that the search behavior of some benthic crustaceans is hindered by rapid water flow and turbulent mixing of prey chemicals, but different sensory strategies employed by other taxa might offset such detrimental effects. Using a laboratory flume, we investigated the odor-tracking behavior of a marine gastropod whelk (Busycon carica) to test the generalization that turbulence interferes with chemically mediated navigation. We exposed individual whelks to turbulent odor plumes in free-stream velocities of 1.5,5, 10 or 15 cm s–1, or with one of two obstructions placed upstream of the odor source in an intermediate flow of 5 cm s–1. Measurements of velocity and stimulus properties confirmed that obstruction treatments increased turbulence intensity and altered the fine-scale structure of downstream odor plumes. In all conditions tested, between 36–63% of test animals successfully located the odor source from 1.5 m downstream with no significant effect of flow treatment. Search behaviors, such as cross-stream meander were reduced at higher flow velocities and in the presence of obstructions, allowing whelks to reach the odor source significantly more quickly than in slower, less turbulent conditions. Our results demonstrate that whelks can respond to chemical information in fast and turbulent flow, and we suggest that these slow-moving predators can forage in hydrodynamic environments where the olfactory abilities of other taxa are limited.
Empirical estimation of free testosterone from testosterone and sex hormone-binding globulin immunoassays
Authors: Ly Lam P , Handelsman David J
Published: March 2005

Background: The growing interest in measuring blood free testosterone (FT) is constrained by the unsuitability of the laborious reference methods for wider adoption in routine diagnostic laboratories. Various alternative derived testosterone measures have been proposed to estimate FT from either additional assay steps or calculations using total testosterone (TT) and sex hormone-binding globulin (SHBG) measured in the same sample. However, none have been critically validated in large numbers of blood samples.

Methods: We analyzed a large dataset comprising over 4000 consecutive blood samples in which FT as well as TT and SHBG were measured. Dividing the dataset into samples with blood TT above and below 5 nM, using a bootstrap regression modeling approach guided by Akaike Information Criterion for model selection to balance parsimony against reduction of residual error, empirical equations were developed for FT in terms of TT and SHBG.

Results: Comparison between the empirical FT equations with the laboratory FT measurements as well as three widely used calculated FT methods showed the empirical FT formulae had superior fidelity with laboratory measurements while previous FT formulae overestimated and deviated systematically from the laboratory FT values.

Conclusion: We conclude that these simple, assumption-free empirical FT equations can estimate accurately blood FT from TT and SHBG measured in the same samples with the present assay methods and have suitable properties for wider application to evaluate the clinical utility of blood FT measurements.
Diabetes and premature menopause: is their co-existence detrimental to the skeleton?
Authors: Hadjidakis D J , Mylonakis A M , Sfakianakis M E , Raptis A E , Raptis S A
Published: March 2005

Objective: Premature menopause is a known risk factor for osteoporosis, whilst the influence of type 2 diabetes on bone mineral density (BMD) is still controversial.

Design and methods: BMD values assessed by dual-energy X-ray absorptiometry (DXA) in L2–L4 vertebrae and the femoral neck (FN) of 40 diabetic women with premature menopause (D-EMP) were compared with those of 60 non-diabetic, prematurely menopausal women (EMP) and 60 diabetic women with normal menopause (D-NMP) who had been matched by age and body mass index (BMI). In all women, the time elapsed since menopause ranged between 10 and 25 years and the duration of diabetes exceeded 75% of the postmenopausal time period. The age of D-EMP women was 58.7±5 years (mean±1 s.d.), age at menopause 39.5±2.7, years since menopause 18.6±4.9, BMI 27.8±4.3 kg/m2 and duration of diabetes 13.9±3.9 years.

Results: Vertebral BMD values of D-EMP women were significantly higher than those of EMP women (0.908±0.135 vs. 0.817±0.14 g/cm2, P = 0.002), although there was no significant difference between D-EMP and D-NMP women (0.886±0.15 g/cm2). No significant differences were observed in FN BMD values between all groups. Age-adjusted BMD values (Z scores) of D-EMP women were higher than EMP women in both anatomic sites (P < 0.01), but did not differ from D-NMP women. In contrast to the other two groups, no statistically significant correlation was observed in D-EMP women between the BMD values of either anatomic area and the time elapsed since menopause. HbA1c values were positively correlated only to vertebral BMD values of the D-EMP group (P < 0.05). No correlation was observed between the BMD values and the duration of diabetes either in D-EMP or in D-NMP women.

Conclusions: Type 2 diabetes seems to positively affect the mineral density of the trabecular bone in women with premature menopause. The duration of diabetes does not appear to influence bone mass.
The natural history of post-traumatic neurohypophysial dysfunction
Authors: Agha Amar , Sherlock Mark , Phillips Jack , Tormey William , Thompson Christopher J
Published: March 2005

Background and objectives: Posterior pituitary function remains poorly investigated after traumatic brain injury (TBI). We report the results of a study designed to prospectively define the natural history of post-traumatic diabetes insipidus (DI) and syndrome of inappropriate antidiuretic hormone secretion (SIADH) using standard reliable methodology.

Design and methods: 50 consecutive patients with severe or moderate TBI (initial Glasgow Coma Scale (GCS) score 3/15–13/15) were prospectively studied on three occasions: at the acute phase and at 6 months and at 12 months following TBI. In the acute phase, DI was diagnosed either by the presence of hypernatraemia in association with hypotonic polyuria or by the water-deprivation test (WDT) and, at 6 and 12 months by the WDT in all patients. Normative data on response to the WDT were obtained from healthy matched volunteers. Functional outcome was assessed using the Glasgow Outcome Scale (GOS).

Results: 13 patients (26%) had DI in the acute post-TBI phase, of whom nine patients recovered by 6 months and one additional patient recovered by 12 months. Of the remaining three patients with permanent DI, two had partial vasopressin deficiency. Acute-phase peak plasma osmolality correlated negatively with the initial GCS scores (r= −0.39,P= 0.005) and with the GOS scores (r= −0.45,P= 0.001). Seven patients had SIADH in the acute phase of TBI but none did at 6 or 12 months. No new cases of DI or SIADH were noted after the acute phase.

Conclusion: This prospective study shows that posterior pituitary dysfunction is common following TBI. Most cases recover completely but there is an appreciable frequency of long-term DI which can be subtle and should be recognized and managed appropriately.
Novel insecticides: Modes of action and resistance mechanism
Authors: Ishaaya Isaac
Published: March 2005

Efforts have been made during the past three decades to develop insecticides with selective properties that act specifically on biochemical sites present in particular insect groups, but whose properties differ from other insecticides. This approach has led to the discovery of compounds that affect the hormonal regulation of molting and developmental processes in insects, e.g., ecdysone agonists (tebufenozide and methoxyfenozide), juvenile hormone mimics (pyriproxyfen and fenoxycarb), and chitin synthesis inhibitors (benzoylphenyl ureas and buprofezin). In addition, compounds that selectively interact with the insect nicotinic acetylcholine receptor such as imidacloprid, acetamiprid, and thiamethoxam have been introduced for the control of aphids, whiteflies, and other insect species.

In this issue, we report on some new insecticides that fit the current approach of pest management programs, such as the new non‐steroidal ecdysone agonist THQ [1‐aroyl‐4‐(arylamino)1,2,3,4‐tetrahydroquinoline], which acts preferentially against mosquitoes with no appreciable effect on other insect groups or mammals. The mode of action of this compound, along with its selectivity, is discussed in detail in the report of Palli et al. Another novel compound reported in this issue is pyradalyl (S‐1812), which was found to act selectively on lepidopterans and thrips. In laboratory assays, pyradalyl was found to act on insect cell lines with no appreciable effect on mammal cell lines. The potential use of this compound in agricultural systems is discussed by Isayama et al.

Three reports in this issue deal with resistance mechanisms and resistance management of novel insecticides. Nauen et al. present an up‐to‐date review on insect resistance mechanisms to neonicotinoids and ways to optimize their use in pest management programs. Horowitz et al. report on Bemisia tabaci biotypes B and Q and their resistance to neonicotinoids and pyriproxyfen. One of the most striking findings in their report is that the Q biotype develops resistance to pyriproxyfen and neoicotinopid faster than biotype B, while the latter exhibits better fitness. The practical implications of these findings are discussed. In another report, Ishaaya et al. present a study detailing the toxicity and cross‐resistance of selected biorational insecticides. Their findings indicate that no appreciable cross‐resistance was observed between the benzoylphenyl urea, novaluron, the juvenile hormone mimic, pyriproxyfen, and the neonicotinoids, acetamiprid and imidacloprid. Hence, these compounds could be used, in alternation, as components in insecticide resistance management programs.
Biotypes B and Q of Bemisia tabaci and their relevance to neonicotinoid and pyriproxyfen resistance
Authors: Horowitz A. Rami , Kontsedalov Svetlana , Khasdan Vadim , Ishaaya Isaac
Published: March 2005

Resistance monitoring for Bemisia tabaci field populations to the juvenile hormone mimic, pyriproxyfen, was conducted from 1996 to 2003 in commercial cotton fields in two areas of Israel: the Ayalon Valley (central Israel) and the Carmel Coast (northwestern Israel). Although the use of pyriproxyfen ceased in these areas in 1996–1997 (because of the resistance), resistance levels to pyriproxyfen declined to some extent in the fields but remained quite stable, and the susceptibility has not been totally restored. Two strains of B. tabaci collected from the Ayalon Valley in the late 1999 and 2002 cotton seasons (AV99L, AV02L) were assayed for their susceptibility to pyriproxyfen at F1, and subsequently a line of each strain was kept under controlled conditions without exposure to insecticides. After maintenance of more than 20 generations under laboratory conditions, the resistance to pyriproxyfen in the untreated strains substantially declined. This decline was concurrent with a replacement of Q biotype by B‐type under non‐insecticidal regimes; apparently B biotype was more competitive than the pyriproxyfen‐resistant Q‐type. Selection under controlled conditions with neonicotinoids on these B. tabaci strains resulted in continued pyriproxyfen resistance, predominantly of Q biotype. Based on our data, applications of either pyriproxyfen or neonicotinoids may select for biotype Q, which would survive to a greater degree where these insecticides are applied. Arch. Insect Biochem. Physiol. 58:216–225, 2005. © 2005 Wiley‐Liss, Inc.
Smart Polyion Complex Micelles for Targeted Intracellular Delivery of PEGylated Antisense Oligonucleotides Containing Acid‐Labile Linkages
Authors: Oishi Motoi , Nagatsugi Fumi , Sasaki Shigeki , Nagasaki Yukio , Kataoka Kazunori
Published: March 2005

A novel pH‐sensitive and targetable antisense ODN delivery system based on multimolecular assembly into polyion complex (PIC) micelles of poly(L‐lysine) (PLL) and a lactosylated poly(ethylene glycol)–antisense ODN conjugate (Lac‐PEG–ODN) containing an acid‐labile linkage (β‐propionate) between the PEG and ODN segments has been developed. The PIC micelles thus prepared had clustered lactose moieties on their peripheries and achieved a significant antisense effect against luciferase gene expression in HuH‐7 cells (hepatoma cells), far more efficiently than that produced by the nonmicelle systems (ODN and Lac‐PEG–ODN) alone, as well as by the lactose‐free PIC micelle. In line with this pronounced antisense effect, the lactosylated PIC micelles showed better uptake than the lactose‐free PIC micelles into HuH‐7 cells; this suggested the involvement of an asialoglycoprotein (ASGP) receptor‐mediated endocytosis process. Furthermore, a significant decrease in the antisense effect (27 % inhibition) was observed for a lactosylated PIC micelle without an acid‐labile linkage (thiomaleimide linkage); this suggested the release of the active (free) antisense ODN molecules into the cellular interior in response to the pH decrease in the endosomal compartment is a key process in the antisense effect. Use of branched poly(ethylenimine) (B‐PEI) instead of the PLL for PIC micellization led to a substantial decrease in the antisense effect, probably due to the buffer effect of the B‐PEI in the endosome compartment, preventing the cleavage of the acid‐labile linkage in the conjugate. The approach reported here is expected to be useful for the construction of smart intracellular delivery systems for antisense ODNs with therapeutic value.
Tumor suppressor gene Runx3 sensitizes gastric cancer cells to chemotherapeutic drugs by downregulating Bcl‐2, MDR‐1 and MRP‐1
Authors: Guo Changcun , Ding Jie , Yao Liping , Sun Li , Lin Tao , Song Ying , Sun Lijun , Fan Daiming
Published: March 2005

The Runx3 gene is a member of the runt domain family transcription factors, key regulators of development and differentiation in metazoan. Recently, Runx3 was identified as a tumor suppressor gene. Loss of Runx3 was found to be associated with genesis and progression of gastric cancer. In this study, we transfected the gastric cancer cell line SGC7901 with eukaryotic expression vector of Runx3. In vitro drug sensitivity assay suggested that SGC7901/Runx3 cells were more sensitive to various chemotherapeutic drugs. Blocking Runx3 expression in immortalized stomach mucosal cells (GES‐1) or gastric cancer cells (SGC7901) by Runx3‐specific small interfering RNA conferred the cells resistance to chemotherapeutic drugs. Flow cytometry examination suggested that expression of Runx3 in gastric cancer cells increased the intracellular accumulation and retention of adriamycin. Semiquantitative RT‐PCR and Western blot suggested that Runx3 downregulated expression of Bcl‐2, MDR‐1 (P‐gp) and MRP‐1. Binding of Runx3 to promoter sequences of Bcl‐2, MDR‐1 and MRP‐1 gene was detected by eletrophoretic mobility shift assay (EMSA) and supershift EMSA. We cloned the MDR‐1 and MRP‐1 gene promoters containing Runx binding sites and constructed the luciferase reporter vectors of these 2 promoters. Luciferase reporter assay suggested that Runx3 inhibited the promoter activity of the MDR‐1 and MRP‐1 promoter in SGC7901 cells. Taken together, our findings suggested that overexpression of Runx3 could sensitize gastric cancer cells to chemotherapeutic drugs by downregulating the Bcl‐2, MDR‐1 and MRP‐1. © 2005 Wiley‐Liss, Inc.
Peripheral blood IFN‐γ‐secreting Vα24+Vβ11+ NKT cell numbers are decreased in cancer patients independent of tumor type or tumor load
Authors: Molling Johan W. , Kölgen Wendy , van der Vliet Hans J.J. , Boomsma Martijn F. , Kruizenga Hinke , Smorenburg Carolien H. , Molenkamp Barbara G. , Langendijk Johannes A. , Leemans C. René , von Blomberg B. Mary E. , Scheper Rik J. , van den Eertwegh Alfons J.M.
Published: March 2005

Natural killer T (NKT) cells are CD1d‐restricted lymphoid cells and are characterized by an invariant T‐cell receptor, which in humans consists of a Vα24 chain paired with a Vβ11 chain. These cells are known for their rapid production of large amounts of cytokines (e.g., IFN‐γ and IL‐4), thereby modulating other cells of the immune system such as T cells, NK cells and dendritic cells. NKT cells have been reported to play important regulatory roles in many immune responses, including antitumor immune responses. Here, we demonstrate an age‐dependent decrease in circulating Vα24+Vβ11+ NKT cell numbers in both healthy controls and cancer patients and demonstrate that in both groups females have higher NKT cell levels compared to males. In a large group of 120 cancer patients, we show that circulating Vα24+Vβ11+ NKT cell numbers are about 50% lower than in age‐ and gender‐matched healthy controls and that this decrease is independent of tumor type or tumor load. This decrease was not restored upon tumor removal by means of surgery or radiotherapy. Even though the percentage of NKT cells that secrete IFN‐γ, as detected by ELISPOT, is normal in cancer patients, the absolute number of circulating IFN‐γ‐secreting NKT cells is reduced. Together, our results suggest that the reduced circulating Vα24+Vβ11+ NKT cell numbers in cancer patients are not affected by tumor load, but might actually reflect a risk factor for tumor development, e.g., by hampering efficient tumor immunosurveillance. © 2005 Wiley‐Liss, Inc.
Effect of diffuse fatty infiltration of the liver on hepatic artery resistance index
Authors: Mihmanli Ismail , Kantarci Fatih , Yilmaz Mehmet Halit , Gurses Bengi , Selcuk Dogan , Ogut Gunduz , Altug Ayca , Uysal Omer
Published: March 2005

Purpose

This study was conducted to evaluate the effect of various degrees of diffuse fatty infiltration of the liver on the hepatic artery resistance index.

Methods

One‐hundred forty subjects were examined using standard color and spectral Doppler sonography protocols. Fatty infiltration of the liver was identified and graded sonographically. The patients were grouped (n = 35 in each of 4 groups) according to the degree of diffuse fatty infiltration of the liver as follows: normal (group 1), mild (group 2), moderate (group 3), and severe (group 4). The resistance index calculated for each patient was the mean of 3 measurements. Mean resistance index of the hepatic artery was then calculated for each group.

Results

The mean resistance index was 0.81 ± 0.04 for group 1, 0.79 ± 0.06 for group 2, 0.75 ± 0.05 for group 3, and 0.73 ± 0.05 for group 4. We found a statistically significant (p < 0.05) decrease in resistance index when comparing groups 3 and 4 with groups 1 and 2 separately.

Conclusions

Hepatic artery resistance index decreases as the severity of diffuse fatty infiltration increases. © 2005 Wiley Periodicals, Inc. J Clin Ultrasound 33:95–99, 2005
Acid‐induced morphological transition of block copolymer brush adsorbed on mica surface
Authors: Cong Yang , Fu Jun , Li Jian , Han Yanchun
Published: March 2005

The morphology and morphological transformation of polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) brushes on mica surfaces have been investigated. PS‐b‐P4VP brushes were adsorbed onto mica surfaces when dip‐coated from dilute solutions because of the strong polar adhesive interaction between the mica surface and the 4VP segments. Porous, bicontinuous layers and isolated clusters were obtained, depending on the concentration of the copolymer solution. These brushes can respond to the acid treatment, adopting elongated conformation. As a result, the relative height of the brushes increased and the lateral dimension decreased. Copyright © 2005 Society of Chemical Industry
Structural and electronic properties of thin fluorite‐structure NiSi2, CoSi2 and FeSi2 interfaces and precipitates in Si
Authors: Wardle M. G. , Goss J. P. , Briddon P. R. , Jones R.
Published: March 2005

Interface geometry and electronic properties of fluorite‐structure NiSi2, CoSi2 and FeSi2 layers in {111} oriented silicon are studied using density functional methods. Of the atomically flat geometries studied, NiSi2 is found to preferentially form an interface where the transition‐metal atoms are 7‐fold coordinated, whereas CoSi2 and γ‐FeSi2 both adopt 8‐fold coordinations. Schottky‐barrier heights are detailed for the low energy interface structures of the three disilicides. The localisation of states introduced below the Si valence band and in the band‐gap are detailed for infinite systems, with preliminary results for finite layers simulated by dislocation dipoles also being discussed. Our calculations support the view that gap‐states for silicide precipitates are associated with bounding dislocations rather than the planar interfaces. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CO2 exchange in a temperate Japanese cypress forest compared with that in a cool‐temperate deciduous broad‐leaved forest
Authors: Takanashi Satoru , Kosugi Yoshiko , Tanaka Yumiko , Yano Masato , Katayama Tatsuya , Tanaka Hiroki , Tani Makoto
Published: March 2005

To examine the characteristics of carbon exchange in coniferous forests, we analysed the seasonal and diurnal patterns of CO2 exchange, as measured using the eddy covariance method, in a Japanese cypress forest in the Kiryu Experimental Watershed (KEW) in central Japan. The net CO2 exchange data during periods of low‐friction velocity conditions and during periods of missing data were interpolated. The daily CO2 uptake was observed throughout the year, with maximum values occurring in early summer. Periods of low carbon uptake were seen in late summer owing to high respiratory CO2 efflux. The diurnal and seasonal patterns of daytime CO2 exchange at KEW were compared with those in a cool‐temperate deciduous forest of the Tomakomai Experimental Forest (TOEF) in Japan. The environmental differences between evergreen and deciduous forests affected the seasonal patterns of carbon uptake. Although there were great differences in the mean monthly air temperatures between the sites, the mean monthly daytime carbon uptake was almost equal at both sites during the peak growing period. The carbon‐uptake values at the same PAR level were greater before noon than after noon, especially at TOEF, suggesting the stomatal regulation of carbon uptake.
GABAB receptor subunit mRNAs are differentially regulated in pituitary melanotropes during development and detection of functioning receptors coincides with completion of innervation
Authors: Purisai Maya Gadhvi , Sands Scott A. , Davis Tracy D. , Price Jeffrey L. , Chronwall Bibie M.
Published: March 2005

This study examines the developmental expression of GABAB receptor subunits (GABAB(1a), GABAB(1b), GABAB(2)) in the pituitary intermediate lobe using in situ hybridization, reverse transcriptase‐polymerase chain reaction, immunohistochemistry, and Western blots. Receptor functionality was studied by baclofen‐stimulated GTPγS binding.

In the adult rat pituitary all three transcripts were detected in melanotropes, but not in glia, of the intermediate lobe. No transcripts of any subunit were detected in the neural lobe. Transcripts of GABAB(1a) and GABAB(1b), but not of GABAB(2), were detected in specific subpopulations of cells in the anterior lobe. All three transcripts were detected in melanotropes on gestational day 18 using in situ hybridization. Reverse transcriptase‐polymerase chain reactions comparing postnatal day 2 and adult transcript levels in the neurointermediate lobe support in situ hybridization data that GABAB(1a) mRNA levels do not change, GABAB(1b) levels increase, and GABAB(2) levels decrease as the rat matures. Thus, GABAB receptor subunit transcripts are differentially regulated in melanotropes during development. In the adult rat both GABAB(1) and GABAB(2) proteins were detected in the neurointermediate lobe using Western blotting and in melanotropes by immunohistochemistry. Developmentally, GABAB(1) protein was not detected until postnatal day 7, but was clearly expressed by postnatal day 15 while GABAB(2) protein could not be detected until postnatal day 15. Functional receptors were found in the intermediate lobe at postnatal day 15 and in the adult. The demonstration of transcripts for GABAB(1a), GABAB(1b) and GABAB(2) subunits at gestational day 18 contrasted with the failure to detect any protein before postnatal day 7, suggesting that the regulation of GABAB subunit isoforms occurs differentially at both the transcriptional and translational level as development progresses. The disparity in the regulation of the receptor subunits may suggest that GABAB(1) could have other functions besides being part of the GABAB receptor heterodimer.
Redistricting in Japan: Lessons for the United States
Authors: CHRISTENSEN RAY
Published: March 2005

Japan is regularly criticized for the malapportionment of its election districts. In contrast, the United States has problems with gerrymandered election districts, even though district boundaries are crafted with meticulous attention paid to population equality among its districts. Japanese redistricting practices prevent gerrymandering of district boundaries, but at a cost of tolerating higher levels of malapportionment than would be allowed in the United States. I analyze the effects of Japan's redistricting rules and find that they have effectively prevented any malapportionment or gerrymandering that benefits a specific political party. I also show that in terms of actual votes cast, the Japanese system produces greater equality between districts than the results obtained in the United States, suggesting that US redistricting practices could be improved by modeling them after the Japanese example.
Executive Turnovers September 2003–September 2004
Authors: INOGUCHI TAKASHI
Published: March 2005

Executive turnovers during September 2003 and September 2004 were moderate, as was the case the preceding year. The reason for this is that Prime Minister Junichiro Koizumi has made it a rule to limit change of cabinet members (Inoguchi, 2004). The Liberal Democratic Party's Presidential election took place in September 2003, giving approval to Koizumi to continue without rival candidates. Koizumi reshuffled his cabinet on September 22, with key cabinet ministers kept intact. They included Chief Cabinet Secretary Yasuo Fukuda, Foreign Minister Yoriko Kawaguchi, Welfare and Labor Minister Chikara Sakaguchi, Economics, Finance and Monetary Affairs Minister Heizo Takenaka. Besides a portfolio to each of the two coalition partners, Koizumi saw to it: (1) that the execution of his structural reform would be spearheaded by a non-compromising reformist academic, Takenaka; (2) that faction-based appointments be reduced to a minimum by appointing those who are not tainted by old-fashioned factional affiliations and ties, i.e., three non-parliamentary members and four female ministers.
Chemical Decomposition of Glutamine in Cell Culture Media: Effect of Media Type, pH, and Serum Concentration
Authors: Ozturk Sadettin S. , Palsson Bernhard O.
Published: March 2005

The chemical decomposition of glutamine to ammonia and pyrrolidonecarboxylic acid was studied at 37°C in a pH range of 6.8–7.8 in different media preparations containing various amounts of fetal bovine serum. The media type influenced the decomposition rate, and the first‐order rate constants increased with increasing pH values. The serum concentration had little or no effect on the decomposition rate. The importance of chemical decomposition of glutamine on the analysis of glutamine and ammonia metabolism was illustrated by an example of batch cultivation of a hybridoma cell line. The difference between the apparent uptake rate of glutamine and the actual uptake rate (which is corrected for the chemical decomposition) is shown to be as high as 200%. Similar discrepancy between the apparent and actual ammonia production rate is observed. Mathematical analysis was carried out to develop the relationship between the apparent and actual glutamine uptake and ammonia production rates. The analysis reveals that there are three important dimensionless parameter ratios that govern the difference between the apparent and actual glutamine uptake and ammonia production rates.
Structural Features of Nonionic Polyglycol Polymer Molecules Responsible for the Protective Effect in Sparged Animal Cell Bioreactors
Authors: Murhammer David W. , Goochee Charles F.
Published: March 2005

The nonionic surfactant Pluronic F‐68 polyol is commonly used to protect cultured animal cells from the detrimental effects of sparging. In this study we investigated the structural features of the Pluronic F‐68 molecule responsible for this protective behavior. Poly(oxyethylene)‐poly(oxypropylene) block copolymer polyols of various molecular weights and percentages of hydrophobe (poly(oxypropylene)), including both Pluronic and reverse Pluronic polyols, were considered. The potential toxicity of these agents was examined in the absence of sparging (i.e., in spinner flasks) by using the attachment‐independent Sf9 insect cell line as a model system. Each polyol resulted in one of three distinct types of behavior in these spinner flask experiments: (1) cells lysed at an exponential rate, (2) inhibition of cell growth (i.e., no net cell growth), or (3) uninhibited cell growth. It was then shown that all of the Pluronic and reverse Pluronic polyols that did not inhibit cell growth provided protection from sparging in the bioreactors used in this study; thus, finding a polyol that protected cells was synonymous with finding one that did not inhibit cell growth. The ability of these polyols to protect animal cells in sparged bioreactors was found to correlate well with the hydrophilic‐lipophilic balance (HLB). Those polyols with the largest HLB values were found to be protective agents. These poly(oxyethylene)‐poly(oxypropylene) polyols were also shown to be more effective protective agents than pure poly(oxyethylene); thus, the presence of the hydrophobe (poly(oxypropylene)) is important in their ability to serve as protective agents.
Physicochemical Changes and Rheological Properties of Starch during Extrusion (A Review)
Authors: Lai L. S. , Kokini J. L.
Published: March 2005

Among all flour components, starches play a key role during extrusion. Starch undergoes several significant structural changes, which include gelatinization, melting, and fragmentation. This review focuses on transformations in starch during extrusion and their effect on rheological properties. The effect of extrusion operating parameters, such as residence time distribution, thermal and mechanical energy input and pressure inside the die, and their effect on rheological properties are reviewed. The relationships between rheological properties and extrudate expansion and final extrudate texture are discussed. The dependence of starch viscosity on temperature, moisture content, time‐temperature history, shear rate, gelatinization, and fragmentation kinetics during extrusion are reviewed.
Production of Catechol by a Bacillus stearothermophilus Transpositional Mutant
Authors: Natarajan M. R. , Oriel P.
Published: March 2005

The phenol‐utilizing thermophile Bacillus stearothermophilus BR219 was mutagenized with transposon Tn916 introduced on a suicide plasmid using electroporation. The resulting mutant BR321 carried Tn916 integrated in the resident plasmid pGGO1 and accumulated catechol throughout the growth phase.
Kinetics of Adsorption of Globular Proteins at an Air‐Water Interface
Authors: Narsimhan Ganesan , Uraizee Farooq
Published: March 2005

Adsorption of globular proteins at an air—water interface from an infinite stagnant medium was modeled as one‐dimensional diffusion in a potential field. The interaction potential experienced by an adsorbing molecule consisted of contributions from electrostatic interactions, work done against the surface pressure to clear area at the interface in order to anchor the adsorbed segments, and the change in the free energy due to exposure of penetrated surface hydrophobic functional groups to air. The assumption of irreversible adsorption is employed in the present analysis. The energy barrier to adsorption, present at sufficiently large surface pressures, was found to be higher for smaller surface hydrophobicities, larger surface pressures, larger size molecules, and oblate orientation of an ellipsoidal molecule. Consequently, more adsorption occurred at larger surface hydrophobicities, smaller size molecules, and for prolate orientation of ellipsoidal molecules. The subphase concentration has been shown to be zero at short times, increasing with time at larger times, and eventually becoming close to the bulk concentration as a result of increasing energy barrier to adsorption. The predicted evolution of surface concentration with time for adsorption of lysozyme at an air—water interface agreed well with the experimental data of Graham and Phillips (1979a).
Continuous Production of Cell‐Free Recombinant Proteins Using Escherichia coli
Authors: Yu Peng , San Ka‐Yiu
Published: March 2005

Continuous production of extracellular recombinant protein using a previously reported periplasmic protein‐release system was successfully demonstrated. The performance of the protein‐releasing system was studied using two types of reactor configuration: a conventional chemostat and a chemostat with a cell‐recycle system. The constitutively expressed α ‐amylase was used as a model protein. In the chemostat experiments, the total α ‐amylase activity increases with decreasing dilution rate—from 135.5 units/mL at a dilution rate of 0.05 h−1 to 2.06 units/mL at a dilution rate of 0.491 h−1. However, the percentage release of α ‐amylase remained relatively constant, at approximately 29%, in the range of dilution rates investigated. The reactor productivity of the target protein reached a maximum of 8.14 units/mL/h at a dilution rate of 0.1 h−1. Application of the releasing system for the continuous production of cell‐free recombinant proteins in a cell‐recycle fermentor was also studied. The reactor performance is significantly better than that of either the chemostat or the batch mode. A total productivity of α ‐amylase at 13.2 units/mL/h with 42% recovery of proteins in the cell‐free form was obtained at a dilution rate of 0.397 h−1 and a bleeding rate of 9.8%.
Viable Cell Recycle with an Inclined Settler in the Perfusion Culture of Suspended Recombinant Chinese Hamster Ovary Cells
Authors: Searles James A. , Todd Paul , Kompala Dhinakar S.
Published: March 2005

The perfusion culture of suspended mammalian cells requires a cell retention device, the best of which will retain all viable cells and reject all nonviable cells and debris. The inclined settler is a passive, simple, inexpensive, and easy‐to‐maintain device that has been shown in the past to selectively remove single nonviable cells of hybridoma cultures. In this work, we have demonstrated the preferential return of viable recombinant Chinese hamster ovary (CHO) cells through the use of a three‐port settler maintained at lower temperatures and vibrated to reduce cell attachment and enhance cell return to the bioreactor. The residence time of CHO cells in the cooled, vibrated settler was determined by flow‐cytometric discrimination of tracer recombinant CHO cells. Cells returning to the bioreactor through the underflow had an average residence time of 1.46 h in the settler. During perfusion cultures with cell densities above 106 cells/mL, cells seen to be stalled within the settler were easily dislodged by periodic air bubbling using a simple back‐flushing procedure in which headspace gas was brought through the settler underflow port. The resuspended cells were returned to the bioreactor within an average of 32 min after bubbling. This study demonstrates that inclined sedimentation technology can be utilized to selectively recycle viable recombinant CHO cells with only a short retention time in an inclined settler.
Optimal Operation Derived by Green's Theorem for the Cell‐Recycle Filter Fermentation Focusing on the Efficient Use of the Medium
Authors: Shimizu Kazuyuki , Furuya Kouji , Taniguchi Masayuki
Published: March 2005

On the basis of the experimental results of Lactobacillus lactis cultivation with cross‐flow filtration, the optimal operation strategy was derived making use of the Green's theorem. It was shown by computer simulation and experiments that optimal operation is superior to the case where the lactate concentration was kept constant, particularly at high cell density cultivation. The performance evaluation was made with respect to the cell productivity for the specified medium.
Clonal Variation in the Spodoptera frugiperda IPLB‐SF21‐AE Insect Cell Population
Authors: Pasumarthy Murali K. , Murhammer David W.
Published: March 2005

Clones have been isolated from the heterogeneous Spodoptera frugiperda IPLB‐SF21‐AE insect cell population. Five of these clones, in addition to the parent cell line and the SF9 cell line (another clonal isolate of the parent cell line), have been compared in regards to morphology, growth, budded virus synthesis, and recombinant protein synthesis. No significant differences in cell morphology were found among these cell lines. There was, however, a significant difference in the average cell size, with diameters ranging from 9.30 ± 0.184 to 11.11 ± 0.22 μm and from 9.17 ± 0.05 to 11.25 ± 0.24 μm for cells growing in Excell 401 serum‐free medium in spinner flask cultures and in TNM‐FH medium supplemented with 10% FBS in tissue flask cultures, respectively. While no significant differences in the growth rates were found in TNM‐FH medium containing 10% calf serum, significant differences were found in Excell 401 serum‐free medium, with population doubling times ranging from 38.5 ± 6.6 to 64.5 ± 6.4 h in spinner flask studies. Significant differences in expression levels of Escherichia coli β‐galactosidase (β‐gal) were also found in both 12‐well plates and spinner flasks. In the 12‐well plate studies, the peak levels of β‐galactosidase obtained by these cell lines ranged from 0.332 ± 0.091 to 0.805 ± 0.117 mg/106 cells and from 0.580 ± 0.130 to 1.458 ± 0.132 mg/106 cells in Excell 401 and Hyclone Hy‐Q serum‐free media, respectively. In the spinner flask studies, peak expression levels ranged from 0.128 ± 0.053 to 0.573 ± 0.215 mg/106 cells in Excell 401 serum‐free medium. Significant differences were also found in the expression levels of budded virus, which ranged from 64 ± 29 to 1125 ± 521 plaque‐forming units (pfu)/cell and from 67 ± 31 to 233 ± 95 pfu/cell for the wildtype and recombinant (β‐gal) Autographa californica nuclear polyhedrosis viruses, respectively.
A Novel Ultrasonic Resonance Field Device for the Retention of Animal Cells
Authors: Doblhoff‐Dier O. , Gaida Th. , Katinger H. , Burger W. , Groschl M. , Benes E.
Published: March 2005

This article describes two types of flow‐through cell retention devices based on the concept of layered piezoelectric resonators. A single‐chamber device is compared to a novel optimized steam‐sterilizable prototype ultrasonic cell separator with improved acoustic design and an integrated cooling circuit, eliminating the problem of local temperature increase caused by the high amplitudes necessary to achieve the separation of animal cells with low acoustic contrast. This setup yields highly reproducible results and is ideal for studying the long‐term effects of ultrasonic sound fields and separation efficiency. The novel two‐chamber system has the potential for scaleability due to the reduction in thermal and acoustic flow, increased field stability, and separation efficiency. Finally, the effect of power input on separation and cell viability is reported. Such flow‐through cell retention systems could be used as systems to retain biomass within the fermentor or as a substitute for centrifugation, with the major advantage of eliminating high‐speed rotational motion.
Microbial Adaptation to Aluminum
Authors: Appanna Vasu D. , Huang John , Prusak‐Sochaczewski Elzbieta , Pierre Micheal St.
Published: March 2005

The presence of aluminum in a minimal mineral medium, with citrate as the sole source of carbon, elicited the production of an exocellular lipid‐rich residue in Pseudomonas fluorescens. Although aluminum affected the growth rate, no apparent diminution in cellular yield was observed in medium supplemented with up to 3 mM of the trivalent metal. While a 10% reduction in cellular yield was recorded in medium with 7.5 mM aluminum, a decrease of 69% was reported in medium supplemented with 50 mM aluminum at stationary phase of growth. The wet weight of the pellet ranged from 5.9 to 70.3 mg mL−1 of culture in medium supplemented with 1–30 mM aluminum. The trivalent metal was immobilized in this precipitate and associated with phosphate moieties. Both neutral lipids and phospholipids constituted the pellet. More than 90% of the weight of the wet pellet was lost following lyophilization. The percentage of aluminum immobilized increased with the concentration of trivalent metal in the medium. Preconditioned cells showed an improved growth rate, and the cellular yield was slightly higher than for unadapted cells.
Purification by Immobilized Metal Affinity Chromatography of Human Atrial Natriuretic Peptide Expressed in a Novel Thioredoxin Fusion Protein
Authors: Wilkinson David L. , Ma Nien ‐Tung , Haught Chris , Harrison Roger G.
Published: March 2005

A fusion protein that contains human atrial natriuretic peptide (ANP) at its carboxy terminus has been genetically engineered with the objective of being able to produce the peptide in a process with a relatively simple purification procedure. The fusion protein also includes a (His)6 metal affinity binding site at the amino terminus, followed by Escherichia coli thioredoxin, a factor Xa protease recognition site, and ANP. With induction of the tac promoter at 30 °C, the expression level of the fusion protein was high (10% of total cell protein as measured by densitometry) and it was almost completely (92%) expressed as a soluble protein in the cytoplasm. A step gradient elution with imidazole of a column of Ni2+ chelated to iminodiacetic acid—agarose saturated with proteins in crude cell extract gave a very nearly pure fusion protein. After digestion of the purified fusion protein with factor Xa protease, ANP of exactly the correct size (to within 2 Da) was observed by coupled HPLC/mass spectrometry.
Issues in the Design of a Multirate Model‐Based Controller for a Nonlinear Drug Infusion System
Authors: Gopinath Ravi , Bequette B. Wayne , Roy R. J. , Kaufman H. , Yu Clem
Published: March 2005

Multivariable controller design for the regulation of mean arterial pressure (MAP) and cardiac output (CO) in congestive heart failure patients is restricted by the limited frequency of CO sampling. Performance criteria for the controller specify maximum allowable transient settling times for both variables, and the design should account for the inherent multirate nature of the process in order to satisfy these criteria. We present a multirate model predictive control (MPC) design for MAP and CO regulation by combined infusion of sodium nitroprusside and dopamine, based on a comprehensive nonlinear model of the system. The multirate MPC algorithm is based on nonlinear quadratic dynamic matrix control. To reduce computation time, we introduce a selective linearization technique that linearizes the model on the basis of trends in the plant‐model mismatch. The problem is complicated by restrictions on initial dopamine infusion, prescribed to avoid extremely slow responses. We present a novel rule‐based override (RBO) to the MPC controller that uses a set of heuristics to initialize dopamine. The performance of the MPC/RBO controller is illustrated using simulation results.
Protein—Polyelectrolyte Phase Boundaries
Authors: Mattison Kevin W. , Brittain Isabelle J. , Dubin Paul L.
Published: March 2005

The separation of proteins by polyelectrolyte coacervation or precipitation is based on electrostatically‐driven complex formation. We have investigated complexation between the globular protein BSA and the polyelectrolyte poly(dimethyldiallylammonium chloride) (PDMDAAC) using light‐scattering techniques to monitor solution turbidity. Turbidimetric pH titrations were used to determine the specific pH values where soluble complex formation is initiated (pHc) and where phase separation occurs (pHφ). These values, collected at different ionic strengths, can be presented as phase boundaries. The effects of macromolecular concentration, protein:polymer concentration ratio (r), and polymer molecular weight upon the phase boundary are examined. The macromolecular concentration and polymer molecular weight have little or no effect on the phase boundary. While pHc is independent of r, pHφ varies inversely with r. The use of phase boundaries in the selection of optimal pH and ionic strength for maximum yield and purity in protein separations is discussed.