bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of a novel carbonic anhydrase, CA XIII, in normal and neoplastic colorectal mucosa
Authors: Kummola Laura , Hämäläinen Jonna M , Kivelä Jyrki , Kivelä Antti J , Saarnio Juha , Karttunen Tuomo , Parkkila Seppo
Published: April 2005

Background

Carbonic anhydrase (CA) isozymes may have an important role in cancer development. Some isozymes control pH homeostasis in tumors that appears to modulate the behaviour of cancer cells. CA XIII is the newest member of the CA gene family. It is a cytosolic isozyme which is expressed in a number of normal tissues. The present study was designed to investigate CA XIII expression in prospectively collected colorectal tumor samples.

Methods

Both neoplastic and normal tissue specimens were obtained from the same patients. The analyses were performed using CA XIII-specific antibodies and an immunohistochemical staining method. For comparison, the tissue sections were immunostained for other cytosolic isozymes, CA I and II.

Results

The results indicated that the expression of CA XIII is down-regulated in tumor cells compared to the normal tissue. The lowest signal was detected in carcinoma samples. This pattern of expression was quite parallel for CA I and II.

Conclusion

The down-regulation of cytosolic CA I, II and XIII in colorectal cancer may result from reduced levels of a common transcription factor or loss of closely linked CA1, CA2 and CA13 alleles on chromosome 8. Their possible role as tumor suppressors should be further evaluated.
Changes in characteristics of veterans using the VHA health care system between 1996 and 1999
Authors: Liu Chuan-Fen , Maciejewski Matthew L , Sales Anne EB
Published: April 2005

Background

The Department of Veterans Affairs' Veterans Health Administration (VHA) provides a health care safety net to veterans. This study examined changes in characteristics of veterans using the VHA health care system between 1996 and 1999 when VHA implemented major organizational changes to improve access of ambulatory care and to provide care to more veterans.

Methods

The study used two cross-sectional samples of the Medical Expenditures Panel Survey (MEPS), a national representative survey, in 1996 and 1999. The 1996 MEPS survey included 1,944 veterans and the 1999 MEPS survey included 1,974 veterans. There were 534 veterans and 740 veterans who used VHA services in 1996 and 1999, respectively.

Results

The proportion of veterans using the VHA system increased from 12.4% in 1996 to 14.6% in 1999. In both years, veterans were more likely to use VHA care if they were older, male, less educated, uninsured, unemployed, and in fair or poor health status. Only two variables, marital status and income, were different between the two years. Married veterans were more likely to use VHA care in 1999, but not in 1996. Veterans with higher incomes had greater odds of using VHA care in 1996, but there was no significant association between income and VHA use in 1999.

Conclusion

Characteristics of VHA users did not fundamentally change despite the reorganization of VHA health care delivery system and changes in eligibility and enrollment policy. The VHA system maintains its safety net mission while attracting more veterans.
Recognizing scientific excellence in the biology of cell adhesion
Authors: Wary Kishore K
Published: April 2005

The prestigious 2005 Japan Prize for Cell Biology has been awarded to Dr. Masatoshi Takeichi, Director of RIKEN Developmental Biology, Kobe, Japan, and Dr. Erkki Ruoslahti, Distinguished Professor, The Burnham Institute, La Jolla, USA for their "Fundamental contribution in elucidating the molecular mechanisms of cell adhesion". The award is scheduled to be presented to the scientists in ceremonies in Tokyo on April 20, 2005 as part of a week-long celebration of "Japan Prize Week".
Physical Interaction and Functional Coupling between ACDP4 and the Intracellular Ion Chaperone COX11, an Implication of the Role of ACDP4 in Essential Metal Ion Transport and Homeostasis
Authors: Guo Dehuang , Ling Jennifer , Wang Mong-Heng , She Jin-Xiong , Gu Jianguo , Wang Cong-Yi
Published: April 2005

Divalent metal ions such as copper, manganese, and cobalt are essential for cell development, differentiation, function and survival. These essential metal ions are delivered into intracellular domains as cofactors for enzymes involved in neuropeptide and neurotransmitter synthesis, superoxide metabolism, and other biological functions in a target specific fashion. Altering the homeostasis of these essential metal ions is known to connect to a number of human diseases including Alzheimer disease, amyotrophic lateral sclerosis, and pain. It remains unclear how these essential metal ions are delivered to intracellular targets in mammalian cells. Here we report that rat spinal cord dorsal horn neurons express ACDP4, a member of Ancient Conserved Domain Protein family. By screening a pretransformed human fetal brain cDNA library in a yeast two-hybrid system, we have identified that ACDP4 specifically interacts with COX11, an intracellular metal ion chaperone. Ectopic expression of ACDP4 in HEK293 cells resulted in enhanced toxicity to metal ions including copper, manganese, and cobalt. The metal ion toxicity became more pronounced when ACDP4 and COX11 were co-expressed ectopically in HEK293 cells, suggesting a functional coupling between them. Our results indicate a role of ACDP4 in metal ion homeostasis and toxicity. This is the first report revealing a functional aspect of this ancient conserved domain protein family. We propose that ACDP is a family of transporter protein or chaperone proteins for delivering essential metal ions in different mammalian tissues. The expression of ACDP4 on spinal cord dorsal horn neurons may have implications in sensory neuron functions under physiological and pathological conditions.
An 800-year reconstruction of Elbe River discharge and German Bight sea-surface salinity
Authors: Scheurle Carolyn , Hebbeln Dierk , Jones Phil
Published: April 2005

On the basis of stable oxygen isotopes (8180), the summer sea-surface salinity of the German Bight, southeastern North Sea, was determined for the past 800 years. In this near-coastal area, salinity is mainly dependent on the freshwater input of the Elbe River discharging its large catchment, which covers an area of 149 000 km2 of central Europe. Therefore, a proxy for Elbe River discharge was reconstructed at the same time, and consequently the 8180 record is also mirroring variations in precipitation within the entire drainage basin. Significant variations in these palaeoenvironmental variables are linked to climatic changes.
Late-Holocene glacier growth in Svalbard, documented by subglacial relict vegetation and living soil microbes
Authors: Humlum Ole , Elberling Bo , Hormes Anne , Fjordheim Kristine , Hansen Odd Harald , Heinemeier Jan
Published: April 2005

Much renewed research interest in Arctic regions stems from the increasing concentration of atmospheric greenhouse gases and the alleged climatic sensitivity of high latitude areas. Glacier and permafrost changes are among a number of proxies used for monitoring past and present Arctic climate change. Here we present observations on frozen in situ soil and vegetation, found below cold-based glacier Longyearbreen (78° 13'N), 2 km upstream from the present glacier terminus. Dating of the relict vegetation indicates that the glacier has increased in length from about 3 km to its present size of about 5 km during the last c. 1100 years. The meteorological setting of non-surging Longyearbreen suggests this example of late-Holocene glacier growth represents a widespread phenomenon in Svalbard and in adjoining Arctic regions. In addition, we use the subglacial permafrozen soil system to evaluate microbial survival capacity over considerable time periods, and we present evidence for microbes having survived more than 1100 years in a subglacial, permafrozen state.
A severe centennial-scale drought in midcontinental North America 4200 years ago and apparent global linkages
Authors: Booth Robert K. , Jackson Stephen T. , Forman Steven L. , Kutzbach John E. , Bettis E. A. , Kreigs Joseph , Wright David K.
Published: April 2005

We present evidence from a variety of physical and biological proxies for a severe drought that affected the mid-continent of North America between 4.1 and 4.3 ka. Rapid climate changes associated with the event had large and widespread ecological effects, including dune reactivation, forest fires and long-term changes in forest composition, highlighting a clear ecological vulnerability to similar future changes. Drought is also documented in the Middle East and portions of Africa and Asia, where it was similar in timing, duration and magnitude to that recorded in the central North American records. Some regions at high latitudes, including northern Europe and Siberia, experienced cooler and/or wetter conditions. Widespread mid-latitude and subtropical drought, associated with increased moisture at some high latitudes, has been linked in the instrumental record to an unusually steep sea surface temperature (SST) gradient between the tropical eastern and western Pacific Ocean (La Ninia) and increased warmth in other equatorial oceans. Similar SST patterns may have occurred at 4.2 ka, possibly associated with external forcing or amplification of these spatial modes by variations in solar irradiance or volcanism. However, changes in SST distribution bracketing the 4.2 ka event are poorly known in most regions and data are insufficient to estimate magnitude of changes in solar and volcanic forcing at this time. Further research is needed to delineate geographical patterns of moisture changes, ecological responses, possible forcing mechanisms and climatology of this severe climatic event.
Response Assessment of Aggressive Non-Hodgkin’s Lymphoma by Integrated International Workshop Criteria and Fluorine-18–Fluorodeoxyglucose Positron Emission Tomography
Authors: Juweid Malik E. , Wiseman Gregory A. , Vose Julie M. , Ritchie Justine M. , Menda Yusuf , Wooldridge James E. , Mottaghy Felix M. , Rohren Eric M. , Blumstein Norbert M. , Stolpen Alan , Link Brian K. , Reske Sven N. , Graham Michael M. , Cheson Bruce D.
Published: April 2005

Purpose

To determine whether a response classification based on integration of fluorine-18–fluorodeoxyglucose positron emission tomography (FDG-PET) into the International Workshop Criteria (IWC) provides a more accurate response assessment than IWC alone in patients with non-Hodgkin's lymphoma (NHL).

Patients and Methods

Fifty-four patients with aggressive NHL who underwent FDG-PET and computed tomography 1 to 16 weeks after four to eight cycles of chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone were assessed for complete response (CR), unconfirmed CR (CRu), partial response (PR), stable disease (SD), and progressive disease (PD) by the IWC and by integrated IWC and FDG-PET (IWC+PET). Progression-free survival (PFS) was also compared between IWC- and IWC+PET-assigned response designations.

Results

By IWC, 17 patients had a CR, seven had a CRu, 19 had a PR, nine had SD, and two had PD. In comparison, by IWC+PET, 35 patients had a CR, 12 had a PR, six had SD, one had PD, and zero had a CRu. In separate multivariate models, PFS was significantly shorter in patients with PR than in those with a CR using IWC (hazard ratio [HR], 8.9; P = .021) or IWC+PET (HR, 29.7; P = .0003). However, when the two classifications were included in the same multivariate model, only IWC+PET was a statistically significant independent predictor for PFS (P = .008 v P = .72 for IWC). In addition, when patients with a PR by IWC and a CR by IWC+PET were compared with those with a CR by IWC and a CR by IWC+PET, there was no significant difference in PFS (HR, 1.6; P = .72), indicating that IWC+PET identified a subset of IWC-PR patients with a more favorable prognosis.

Conclusion

Compared with IWC, the IWC+PET-based assessment provides a more accurate response classification in patients with aggressive NHL.
Randomized Comparison of ABVD Chemotherapy With a Strategy That Includes Radiation Therapy in Patients With Limited-Stage Hodgkin’s Lymphoma: National Cancer Institute of Canada Clinical Trials Group and the Eastern Cooperative Oncology Group
Authors: Meyer Ralph M. , Gospodarowicz Mary K. , Connors Joseph M. , Pearcey Robert G. , Bezjak Andrea , Wells Woodrow A. , Burns Bruce F. , Winter Jane N. , Horning Sandra J. , Dar A. Rashid , Djurfeldt Marina S. , Ding Keyue , Shepherd Lois E.
Published: April 2005

Purpose

We report results of a randomized trial comparing ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) chemotherapy alone with treatment that includes radiation therapy in patients with limited-stage Hodgkin's lymphoma.

Patients and Methods

Patients with nonbulky clinical stage I to IIA Hodgkin's lymphoma were stratified into favorable and unfavorable risk cohorts. Patients allocated to radiation-containing therapy received subtotal nodal radiation if favorable risk or combined-modality therapy if unfavorable risk. Patients allocated to ABVD received four to six treatment cycles.

Results

We evaluated 399 patients. Median follow-up is 4.2 years. In comparison with ABVD alone, 5-year freedom from disease progression is superior in patients allocated to radiation therapy (P = .006; 93% v 87%); no differences in event-free survival (P = .06; 88% v 86%) or overall survival (P = .4; 94% v 96%) were detected. In a subset analyses comparing patients stratified into the unfavorable cohort, freedom from disease progression was superior in patients allocated to combined-modality treatment (P = .004; 95% v 88%); no difference in overall survival was detected (P = .3; 92% v 95%). Of 15 deaths observed, nine were attributed to causes other than Hodgkin's lymphoma or acute treatment-related toxicity.

Conclusion

In patients with limited-stage Hodgkin's lymphoma, no difference in overall survival was detected between patients randomly assigned to receive treatment that includes radiation therapy or ABVD alone. Although 5-year freedom from disease progression was superior in patients receiving radiation therapy, this advantage is offset by deaths due to causes other than progressive Hodgkin's lymphoma or acute treatment-related toxicity.
Phase III Study of the Eastern Cooperative Oncology Group (ECOG 2597): Induction Chemotherapy Followed by Either Standard Thoracic Radiotherapy or Hyperfractionated Accelerated Radiotherapy for Patients With Unresectable Stage IIIA and B Non–Small-Cell Lung Cancer
Authors: Belani Chandra P. , Wang Wei , Johnson David H. , Wagner Henry , Schiller Joan , Veeder Michael , Mehta Minesh
Published: April 2005

Purpose

To compare once-daily radiation therapy (qdRT) with hyperfractionated accelerated radiation therapy (HART) after two cycles of induction chemotherapy.

Patients and Methods

Eligible patients were treatment naive, and had stage IIIA and B unresectable non-small-cell lung cancer, Eastern Cooperative Oncology Group performance status 0/1, and normal organ function. Induction chemotherapy consisted of two cycles of carboplatin area under time-concentration curve 6 mg/mL · min plus paclitaxel 225 mg/m2 on day 1. RT consisted of arm 1 (qdRT), 64 Gy (2 Gy/d), versus arm 2 (HART), 57.6 Gy (1.5 Gy tid for 2.5 weeks). A total of 388 patients were needed to detect a 50% increase in median survival from 14 months of qdRT to 21 months of HART; accrual was not achieved and the study closed prematurely.

Results

Of 141 patients enrolled, 83% were randomly assigned after chemotherapy to qdRT (n = 59) or HART (n = 60). Median survival was 20.3 and 14.9 months for HART and qdRT, respectively (P = .28). Overall response was 25% and 22% for HART and qdRT, respectively (P = .69). Two- and 3-year survival was 44% and 34% for HART, and 24% and 14% for qdRT, respectively. Grade ≥ 3 toxicities included esophagitis in 14 v nine patients, and pneumonitis in 0 v 6 patients for HART and qdRT, respectively. Any subsequent trials of the HART regimen must address the issues that led to early closure, including slow accrual, logistics of HART, mucosal toxicity, and the fact that concurrent chemoradiotherapy now seems more effective than sequential treatment.

Conclusion

After two cycles of induction chemotherapy with carboplatin-paclitaxel, HART is feasible with an acceptable toxicity profile. Although statistical significance was not achieved and the study closed early, there was a positive statistical trend suggesting a survival advantage with the HART regimen.
Intensity of18Fluorodeoxyglucose Uptake in Positron Emission Tomography Distinguishes Between Indolent and Aggressive Non-Hodgkin’s Lymphoma
Authors: Schöder Heiko , Noy Ariela , Gönen Mithat , Weng Lijun , Green David , Erdi Yusuf E. , Larson Steven M. , Yeung Henry W.D.
Published: April 2005

Purpose

18Fluorodeoxyglucose positron emission tomography (FDG PET) is widely used for the staging of lymphoma. We investigated whether the intensity of tumor FDG uptake could differentiate between indolent and aggressive disease.

Materials and Methods

PET studies of 97 patients with non-Hodgkin's lymphoma who were untreated or had relapsed and/or persistent disease and had not received treatment within the last 6 months were analyzed, and the highest standardized uptake value (SUV) per study was recorded. Correlations were made with histopathology.

Results

FDG uptake was lower in indolent than in aggressive lymphoma for patients with new (SUV, 7.0 ± 3.1 v 19.6 ± 9.3; P < .01) and relapsed (SUV, 6.3 ± 2.7 v 18.1 ± 10.9; P = .04) disease. Despite overlap between indolent and aggressive disease in the low SUV range (indolent, 2.3 to 13.0; aggressive, 3.2 to 43.0), all cases of indolent lymphoma had an SUV ≤ 13. A receiver operating characteristic (ROC) analysis demonstrated that the SUV distinguished reasonably well between aggressive and indolent disease (area under ROC curve, 84.7%), and an SUV > 10 excluded indolent lymphoma with a specificity of 81%. With a higher cutoff for the SUV, the specificity would have been higher.

Conclusion

FDG uptake is lower in indolent than in aggressive lymphoma. Patients with NHL and SUV > 10 have a high likelihood for aggressive disease. This information may be helpful if there is discordance between biopsy and clinical behavior.
Effect of the anticancer drug oracin on mouse liver topoisomerases I and II
Authors: Stuchlík Stanislav , Turn̂a Ján , Miko Milan
Published: April 2005

The inhibitory effect of oracin on the activities of topoisomerases I and II isolated from the nuclei of mice liver tissue was studied. This drug showed a 100% inhibitory effect at 5 μm and 50% inhibition at 1 μm on topoisomerase II activity, while the activity of topoisomerase I at these concentrations was not inhibited.
Multidrug resistance modulator interactions with neutral and anionic liposomes: membrane binding affinity and membrane perturbing activity
Authors: Castaing Madeleine , Loiseau Alain , Mulliert Guillermo
Published: April 2005

A variety of cationic lipophilic compounds (modulators) have been found to reverse the multidrug resistance of cancer cells. In order to determine the membrane perturbing efficacy and the binding affinity of such drugs in neutral and anionic liposomes, the leakage of Sulfan blue induced by five modulators bearing different electric charges was quantified using liposomes with and without phosphatidic acid (xEPA = 0 and 0.1), at four lipid concentrations. The binding isotherms were drawn up using the indirect method based on the dependency of the leakage rate on the modulator and the lipid concentrations. Upon inclusion of negatively charged lipids in the liposomes: (i) the binding of cationic drugs was favoured, except in a case where modulator aggregation occurred in the lipid phase; (ii) the drugs with a net electric charge greater than 1.1 displayed a greater enhancement in their potency to produce membrane perturbation; and (iii) the EPA effect on membrane permeation was due mainly to that on membrane perturbation (≥50%) and, to a lesser extent, to that on the binding affinity (≤50%). The present study provides evidence that drug-membrane interactions are the result of a complex interplay between the structural and electrical characteristics of the drugs and those of the membranes.
Protective effect of aqueous garlic extract against naphthalene-induced oxidative stress in mice
Authors: Omurtag Gülden Z , Güranlioǧlu F Deniz , Şehirli Özer , Arbak Serap , Uslu Bahar , Gedik Nursal , Şener Göksel
Published: April 2005

The aim of this study was to investigate the possible protective effects of aqueous garlic extract (AGE) against naphthalene-induced oxidative changes in liver, kidney, lung and brain of mice. Balb/c mice (25–30 g) of either sex were divided into five groups each comprising 10 animals. Mice received for 30 days: 0.9% NaCl, i.p. (control); corn oil, i.p; AGE in a dose of 125 mg kg−1, i.p.; naphthalene in a dose of 100 mg kg−1, i.p. (dissolved in corn oil); and AGE (in a dose of 125 mg kg−1, i.p.) plus naphthalene (in a dose of 100 mg kg−1, i.p.). After decapitation, liver, kidney, lung and brain tissues were excised. Malondialdehyde (MDA) and glutathione (GSH) levels and myeloperoxidase activity (MPO) were determined in the tissues, while oxidant-induced tissue fibrosis was determined by collagen content. Tissues were also examined microscopically. Serum aspartate aminotransferase, alanine aminotransferase levels and blood urea nitrogen and creatinine concentrations were measured for the evaluation of hepatic and renal function, respectively. MDA and GSH levels were also assayed in serum samples. In the naphthalene-treated group, GSH levels decreased significantly, while MDA levels, MPO activity and collagen content increased in the tissues (P< 0.01–0.001), suggesting oxidative organ damage, which was also verified histologically. In the AGE-treated naphthalene group, all of these oxidant responses were reversed significantly (P< 0.05–0.01). Hepatic and renal function test parameters, which increased significantly (P< 0.001) following naphthalene administration, decreased (P< 0.05–0.001) after AGE treatment. The results demonstrate the role of oxidative mechanisms in naphthalene-induced tissue damage. The antioxidant properties of AGE ameliorated oxidative organ injury due to naphthalene toxicity.
The use of hypromellose in oral drug delivery
Authors: Li Chi L , Martini Luigi G , Ford James L , Roberts Matthew
Published: April 2005

Hypromellose, formerly known as hydroxypropylmethylcellulose (HPMC), is by far the most commonly employed cellulose ether used in the fabrication of hydrophilic matrices. Hypromellose provides the release of a drug in a controlled manner, effectively increasing the duration of release of a drug to prolong its therapeutic effect. This review provides a current insight into hypromellose and its applicability to hydrophilic matrices in order to highlight the basic parameters that affect its performance. Topics covered include the chemical, thermal and mechanical properties of hypromellose, hydration of the polymer matrices, the mechanism of drug release and the influence of tablet geometry on drug-release rate. The inclusion of drug-release modifiers within hypromellose matrices, the effects of dissolution media and the influence of both the external environment and microenvironment pH within the gel matrix on the properties of the polymer are also discussed.
Transport mechanism and substrate specificity of human organic anion transporter 2 (hOat2 [SLC22A7])
Authors: Kobayashi Yasuna , Ohshiro Naomi , Sakai Ryoko , Ohbayashi Masayuki , Kohyama Noriko , Yamamoto Toshinori
Published: April 2005

Human organic anion transporter 2 (hOat2 [SLC22A7]) is highly expressed in the human liver. Although localization, gene expression, substrate specificity and transport mechanisms of other human Oat isoforms such as human Oat1 (hOat1), human Oat3 (hOat3) and human Oat4 (hOat4) have been elucidated, information concerning human Oat2 (hOat2) is less defined. The objective of this study was to provide further information on the transport mechanism and substrate specificity of hOat2. When expressed in Xenopus laevis oocytes, the transport of organic compounds mediated by hOat2 was not affected by the replacement of extracellular sodium with lithium, choline and mannitol. The uptake of estrone sulfate (ES) in hOat2-expressing oocytes was significantly trans-stimulated by preloading the oocytes with fumarate and succinate, but not glutarate. Moreover, we observed that hOat2 mediates the transport of bumetanide, ES, glutarate, dehydroepiandrosterone sulfate, allopurinol, prostaglandin E2, 5-fluorouracil, paclitaxel and L-ascorbic acid. These compounds are identified for the first time as hOat2 substrates. A wide range of structurally unrelated organic compounds inhibited the hOat2-mediated uptake of tetracycline, except for sulfobromophthalein. All of these findings indicate that hOat2 is a sodium-independent multi-specific organic anion/dimethyldicarboxylate exchanger. Our present findings thus provide further insights into the role of hOat2 in hepatic drug transport.
Improvement of diabetic states in streptozotocin-induced type 1 diabetic rats by vanadyl sulfate in enteric-coated capsules
Authors: Fugono Jun , Yasui Hiroyuki , Sakurai Hiromu
Published: April 2005

Chronic oral administration of vanadyl sulfate has recently been shown to improve the state of type 2 diabetic subjects. Mild gastrointestinal symptoms and side effects, however, have been observed in some subjects. To find safer and more effective dosages, we have developed an enteric-coated capsule containing solid vanadyl sulfate (ECC/VS), which enhances the bioavailability of vanadyl sulfate to almost double that of vanadyl sulfate solution. ECC/VS was chronically administered to treat streptozotocin-induced diabetic rats (STZ-rats), an animal model of type 1 diabetes mellitus, and an equivalent blood-glucose-lowering effect was observed at half the doses of vanadyl sulfate alone. In addition, we observed almost the same total vanadium levels in the serum after chronic administration of ECC/VS as those of vanadyl sulfate alone, suggesting that plasma vanadium levels correlate with the hypoglycaemic activity of vanadyl sulfate. These results indicate that oral ECC/VS improves the diabetic state by enhancing the uptake of vanadium in STZ-rats. These findings will be useful in designing clinical trials of vanadyl sulfate for diabetic subjects.
Isobolographic analysis of the sedative interaction between six central nervous system depressant drugs and Valeriana edulis hydroalcoholic extract in mice*
Authors: Ugalde Martha , Reza Victoria , González-Trujano Ma Eva , Avula Bharathi , Khan Ikhlas A , Navarrete Andrés
Published: April 2005

It has been declared frequently that valerian may potentiate the effect of other central nervous system (CNS) depressant drugs, however there has been a lack of experimental data. We have evaluated the profile of the interactions between the ethanol extract of Valeriana edulis spp procera and six CNS depressant drugs using an exploratory model to test the sedative effect in mice. All the compounds tested showed a dose-dependent sedative effect with the following ED50 values: valerian 181.62, diazepam 1.21, ethanol 1938, pentobarbital 11.86, buspirone 1.04, haloperidol 0.41 and diphenhydramine 17.06 mg kg−1. An isobolographic analysis was used to evaluate the sedative interaction of the intraperitoneal co-administration of 1:1 fixed-ratio combination of equi-effective doses of valerian extract with each CNS depressant drug. The ED50 theoretical (Zadd) and experimental (Zexp) for each combination were: valerian + diazepam, Zadd = 91.41 mg kg−1, Zexp = 81.64 mg kg−1; valerian + ethanol, Zadd = 1060.22 mg kg−1, Zexp = 687.89 mg kg−1; valerian + pentobarbital, Zadd = 96.74 mg kg−1, Zexp = 151.83 mg kg−1; valerian + buspirone, Zadd = 91.33 mg kg−1, Zexp = 112.73 mg kg−1; valerian + haloperidol, Zadd = 91.01 mg kg−1, Zexp = 91.52 mg kg−1; valerian + diphenhydramine, Zadd = 99.34 mg kg−1, Zexp = 123.52 mg kg−1. Neither synergistic nor attenuate effects were found in any of the combinations evaluated. We concluded that the valerian extract did not potentiate the sedative effect of commonly prescribed CNS depressant drugs as was expected. The additive effect found through the isobolographic analysis suggested that the sedative effect of V. edulis resulted from the activation of common mechanisms of haloperidol, diazepam, buspirone, pentobarbital, diphenhydramine and ethanol.
Modulation of intestinal transport of 2,4-dinitrophenyl-S-glutathione, a multidrug resistance-associated protein 2 substrate, by bilirubin treatment in rats
Authors: Yokooji Tomoharu , Murakami Teruo , Ogawa Kumiko , Yumoto Ryoko , Nagai Junya , Takano Mikihisa
Published: April 2005

The effect of bilirubin treatment on intestinal transport of 2,4-dinitrophenyl-S-glutathione (DNP-SG), a substrate of multidrug resistance-associated protein 2 (MRP2), after application of 1-chloro-2, 4-dinitrobenzene (CDNB), a precursor of DNP-SG, was examined in rat intestine by the in-vitro everted sac, in-situ re-circulating perfusion, and in-situ loop methods. CDNB was taken up rapidly by jejunum and ileum, and the consequent intestinal efflux of DNP-SG, a glutathione conjugated metabolite of CDNB, was significantly higher in jejunum than in ileum in the in-situ and in-vitro studies. Co-administration of bilirubin (100 μM), as well as probenecid (1 mM) or ciclosporin (100 μM), with CDNB decreased the DNP-SG efflux in jejunum significantly, but not in ileum. The suppression of DNP-SG efflux in jejunum was also observed after intravenous administration of bilirubin (85.5 μmol kg−1), in which plasma bilirubin glucuronide levels were approximately 100 μM. In the in-vitro metabolism study, bilirubin exerted no significant effect on CDNB metabolism in the intestinal S9 fraction (supernatant of 9000 g). These results suggested that the diseased states accompanied with hyperbilirubinaemia might have increased the intestinal absorption, or oral bioavailability, of MRP2 substrates by suppressing MRP2 function at the proximal intestinal region.
Pre-clinical pharmacokinetics of the cyclooxygenase-inhibiting nitric oxide donor (CINOD) AZD3582
Authors: Fagerholm U , Breuer O , Swedmark S , Hoogstraate J
Published: April 2005

The pre-clinical pharmacokinetics of AZD3582 (4-(nitrooxy)butyl-(2S)-2-(6-methoxy-2-naphthyl) propanoate) and its primary metabolites (naproxen and nitrate) were evaluated. AZD3582 had intermediate and passive intestinal permeability (40 times lower than for naproxen), high systemic plasma clearance (CL), substantial gastrointestinal hydrolysis, intermediate volume of distribution (Vss; ≥3.4 L kg−1) and half-life (t1/2; 7 h), negligible plasma protein binding (∼0.1%), low/intermediate oral uptake (≥13% as intact substance) and low and varying oral bioavailability (mean 1.4% in minipigs and 3.9% in dogs). Following administration of therapeutically relevant oral doses, plasma concentrations of AZD3582 were very low (≤ 13 nM in minipigs and ≤442 nM in dogs; rat data not available) and varying, and accumulation was not apparent. The pharmacokinetics of AZD3582 did not show apparent dose-, time- or gender-related dependency. In blood and intestine, AZD3582 was hydrolysed to naproxen, nitrate and other metabolites. The rate of this conversion was higher in rats than in non-rodents, including man. Despite near-complete to complete uptake of the oral dose, AZD3582 administration resulted in a lower bioavailability (F) of total naproxen than naproxen administration: 55% and 85% relative bioavailability (Frel) in rats and minipigs, respectively. An increased distribution to metabolizing tissues of naproxen (as AZD3582), and thereby enhanced naproxen CL, is believed to be responsible. Following dosing of AZD3582 or naproxen, the t1/2 of naproxen was 5, 9–10 and >40 h in rats, minipigs and dogs, respectively. The Vss and CL for naproxen were small. Plasma protein binding was extensive, and saturation was observed within the therapeutic dose and concentration range. Intake of food prolonged the systemic absorption of naproxen in the minipig. The pharmacokinetics of naproxen did not show apparent time- or gender-related dependency. Following oral dosing of [3H]-, [14C]- and [15N]-AZD3582, most [14C]- and [3H]-activity was excreted in urine and expired air, respectively. Seventeen per cent of [15N] was recovered in minipig urine as [15N]-nitrate. About 30% of [3H]-activity (naproxen and/or naproxen-related metabolites) was excreted in bile and re-absorbed. Concentrations of [14C]-activity (nitrooxy-butyl group and/or its metabolites) in milk were higher than in plasma and [3H]-activity in milk. [3H]- and [14C]-excretion data indicated that intact AZD3582 was not excreted in urine, bile or milk to a significant extent. There was no apparent consistency between tissue distribution of [14C]- and [3H]-activity in the rat, which suggests rapid and extensive metabolism of extravascularly distributed AZD3582. A substantial increase of plasma nitrate levels was found after single and repeated oral doses of AZD3582 in the minipig. No inhibition or induction of CYP450 was found.
A site-specific controlled-release system for metformin
Authors: Di Colo Giacomo , Zambito Ylenia , Baggiani Andrea , Carelli Vera , Serafini Maria Francesca
Published: April 2005

Oral absorption of the antihyperglycaemic agent metformin hydrochloride (MF-HCl) is confined to the upper part of the intestine, therefore rational controlled-release formulations of this drug should ensure a complete release during transit from stomach to jejunum. The aim of this study was the preparation of a system able to sustain release of high MF-HCl doses in compliance with the above requirement. Matrices (6 mm diameter; 50 mg weight) comprising varying drug-Precirol ATO 5 ratios were prepared by compression. The matrix containing 70% drug was coated on one face with Eudragit L100–55. Drug release to simulated gastric (SGF), jejunal (SJF) and ileal (SIF) fluids in sequence was studied using a modified USP rotating basket method. Release depended on drug load whereas it was independent of dissolution medium pH and hydrodynamics. Release kinetics were of √t type and were determined by drug diffusion in aqueous pores created in the matrix by drug dissolution. An equation correlating rate-determining factors was developed, whereby the release pattern could be optimized. The half-coated matrix started release in SGF and completed it in SJF. The half-coated matrix, synchronizing drug release and matrix transit across the small intestine, may improve drug bioavailability and reduce side effects.
Influence of the Ginkgo extract EGb 761 on rat liver cytochrome P450 and steroid metabolism and excretion in rats and man
Authors: Chatterjee Shyam S , Doelman Cees J A , Nöldner Michael , Biber Anton , Koch Egon
Published: April 2005

Extracts from leaves of Ginkgo biloba L. are among the most used herbal medicinal products worldwide. Based on in-vitro tests and studies in rats, concern has been expressed that intake of Ginkgo extracts may affect hepatic metabolism of xenobiotics and cause drug interactions, although no evidence for modulation of cytochrome P450 (CYP450) enzyme activity was obtained in human trials. Because of these contradictory findings, we investigated the effects of the standardised extract EGb 761 on hepatic CYP450 in rats. EGb 761 (100 mg kg−1 daily, p.o., for 4 days) strongly increased liver CYP450 content and altered the ex-vivo biotransformation of androstendione, as well as metabolism of endogenous steroids. However, in human subjects no effect on the urinary steroid profile was observed after intake of EGb 761 for 28 days (240 mg daily). These results indicate that the effects of EGb 761 on drug metabolising enzymes are specific for rats and may not be extrapolated to man.
Nelumbinis Semen reverses a decrease in hippocampal 5-HT release induced by chronic mild stress in rats
Authors: Kang Moonkyu , Pyun Kwang-Ho , Jang Choon-Gon , Kim Hyuntaek , Bae Hyunsu , Shim Insop
Published: April 2005

Depression is associated with a dysfunctional serotonin system. Recently, several lines of evidence have suggested that a very important evoking factor in depression may be a serotonin deficit in the hippocampus. This study assessed the antidepression effects of Nelumbinis Semen (NS) through increasing serotonin concentrations under normal conditions and reversing a decrease in serotonin concentrations in rat hippocampus with depression-like symptoms induced by chronic mild stress (CMS). Using an in-vivo microdialysis technique, the serotonin-enhancing effect of NS on rat hippocampus was investigated and its effects compared with those of two well-known antidepressants, Hypericum perforatum (St John's wort) and fluoxetine (Prozac). Rats were divided into five groups: saline-treated normal, without CMS; saline-treated stress control; NS-, St John's wort- and fluoxetine-treated rats under CMS for 8 weeks or no stress treatment. NS and fluoxetine significantly increased serotonin in normal conditions and reversed a CMS-induced decrease in serotonin release in the hippocampus (P< 0.05 compared with normal group or control group under CMS). These results suggest that NS increases the serotonin levels normally decreased in depression, resulting in an enhancement of central serotonergic transmission and possible therapeutic action in depression. It is suggested that NS may present an antidepressant effect through enhancement of serotonin.
On the aerodynamics of leading-edge high-lift devices of avian wings
Authors: Meseguer J , Franchini S , Pérez-Grande I , Sanz J L
Published: April 2005

The alula is a high-lift device located at the leading edge of bird wings that allows these animals to fly at large angles of attack and low speeds without wing stalling. The influence of the alula in the wing aerodynamics seems to be similar to that of leading-edge slats in aircraft wings. Aiming to clarify the role of the alula in the aerodynamics of the bird wings, the aerodynamic forces generated by a model simulating the wing of a pigeon equipped with different alulae were measured in a wind tunnel. Experimental results show that alula deflection causes the boundary layer to remain attached at large values of the angle of attack (at least in the wing area protected by this device: from the alula position to the wing root), so that lift forces can be up to 22 per cent higher than those measured at the same angle of attack without alula deflection.
Exon repression by polypyrimidine tract binding protein
Authors: AMIR-AHMADY BATOUL , BOUTZ PAUL L. , MARKOVTSOV VADIM , PHILLIPS MARTIN L. , BLACK DOUGLAS L.
Published: April 2005

Polypyrimidine tract binding protein (PTB) is known to silence the splicing of many alternative exons. However, exons repressed by PTB are affected by other RNA regulatory elements and proteins. This makes it difficult to dissect the structure of the pre-mRNP complexes that silence splicing, and to understand the role of PTB in this process. We determined the minimal requirements for PTB-mediated splicing repression. We find that the minimal sequence for high affinity binding by PTB is relatively large, containing multiple polypyrimidine elements. Analytical ultracentrifugation and proteolysis mapping of RNA cross-links on the PTB protein indicate that most PTB exists as a monomer, and that a polypyrimidine element extends across multiple PTB domains. The high affinity site is bound initially by a PTB monomer and at higher concentrations by additional PTB molecules. Significantly, this site is not sufficient for splicing repression when placed in the 3′ splice site of a strong test exon. Efficient repression requires a second binding site within the exon itself or downstream from it. This second site enhances formation of a multimeric PTB complex, even if it does not bind well to PTB on its own. These experiments show that PTB can be sufficient to repress splicing of an otherwise constitutive exon, without binding sites for additional regulatory proteins and without competing with U2AF binding. The minimal complex mediating splicing repression by PTB requires two binding sites bound by an oligomeric PTB complex.
The human U5 snRNP 52K protein (CD2BP2) interacts with U5-102K (hPrp6), a U4/U6.U5 tri-snRNP bridging protein, but dissociates upon tri-snRNP formation
Authors: LAGGERBAUER BERNHARD , LIU SUNBIN , MAKAROV EVGENY , VORNLOCHER HANS-PETER , MAKAROVA OLGA , INGELFINGER DIERK , ACHSEL TILMANN , LÜHRMANN REINHARD
Published: April 2005

The U5 snRNP plays an essential role in both U2- and U12-dependent splicing. Here, we have characterized a 52-kDa protein associated with the human U5 snRNP, designated U5-52K. Protein sequencing revealed that U5-52K is identical to the CD2BP2, which interacts with the cytoplasmic portion of the human T-cell surface protein CD2. Consistent with it associating with an snRNP, immunofluorescence studies demonstrated that the 52K protein is predominantly located in the nucleoplasm of HeLa cells, where it overlaps, at least in part, with splicing-factor compartments (or “speckles”). We further demonstrate that the 52K protein is a constituent of the 20S U5 snRNP, but is not found in U4/U6.U5 tri-snRNPs. Thus, it is the only 20S U5-specific protein that is not integrated into the tri-snRNP and resembles, in this respect, the U4/U6 di-snRNP assembly factor Prp24p/p110. Yeast two-hybrid screening and pulldown assays revealed that the 52K protein interacts with the U5-specific 102K and 15K proteins, suggesting that these interactions are responsible for its integration into the U5 particle. The N-terminal two-thirds of 52K interact with the 102K protein, whereas its C-terminal GYF-domain binds the 15K protein. As the latter lacks a proline-rich tract, our data indicate that a GYF-domain can also engage in specific protein–protein interactions in a polyproline-independent manner. Interestingly, the U5-102K protein has been shown previously to play an essential role in tri-snRNP formation, binding the U4/U6-61K protein. The interaction of 52K with a tri-snRNP bridging protein, coupled with its absence from the tri-snRNP, suggests it might function in tri-snRNP assembly.
The N-terminal extension of Escherichia coli ribosomal protein L20 is important for ribosome assembly, but dispensable for translational feedback control
Authors: GUILLIER MAUDE , ALLEMAND FRÉDÉRIC , GRAFFE MONIQUE , RAIBAUD SOPHIE , DARDEL FRÉDÉRIC , SPRINGER MATHIAS , CHIARUTTINI CLAUDE
Published: April 2005

The Escherichia coli autoregulatory ribosomal protein L20 consists of two structurally distinct domains. The C-terminal domain is globular and sits on the surface of the large ribosomal subunit whereas the N-terminal domain has an extended shape and penetrates deep into the RNA-rich core of the subunit. Many other ribosomal proteins have analogous internal or terminal extensions. However, the biological functions of these extended domains remain obscure. Here we show that the N-terminal tail of L20 is important for ribosome assembly in vivo. Indeed, a truncated version of L20 without its N-terminal tail is unable to complement the deletion of rplT, the gene encoding L20. In addition, this L20 truncation confers a lethal-dominant phenotype, suggesting that the N-terminal domain is essential for cell growth because it could be required for ribosome assembly. Supporting this hypothesis, partial deletions of the N-terminal tail of the protein are shown to cause a slow-growth phenotype due to altered ribosome assembly in vivo as large amounts of intermediate 40S ribosomal particles accumulate. In addition to being a ribosomal protein, L20 also acts as an autogenous repressor. Using L20 truncations, we also show that the N-terminal tail of L20 is dispensable for autogenous control.
Structural RNA has lower folding energy than random RNA of the same dinucleotide frequency
Authors: CLOTE PETER , FERRÉ FABRIZIO , KRANAKIS EVANGELOS , KRIZANC DANNY
Published: April 2005

We present results of computer experiments that indicate that several RNAs for which the native state (minimum free energy secondary structure) is functionally important (type III hammerhead ribozymes, signal recognition particle RNAs, U2 small nucleolar spliceosomal RNAs, certain riboswitches, etc.) all have lower folding energy than random RNAs of the same length and dinucleotide frequency. Additionally, we find that whole mRNA as well as 5′-UTR, 3′-UTR, and cds regions of mRNA have folding energies comparable to that of random RNA, although there may be a statistically insignificant trace signal in 3′-UTR and cds regions. Various authors have used nucleotide (approximate) pattern matching and the computation of minimum free energy as filters to detect potential RNAs in ESTs and genomes. We introduce a new concept of the asymptotic Z-score and describe a fast, whole-genome scanning algorithm to compute asymptotic minimum free energy Z-scores of moving-window contents. Asymptotic Z-score computations offer another filter, to be used along with nucleotide pattern matching and minimum free energy computations, to detect potential functional RNAs in ESTs and genomic regions.
A reduced level of charged tRNAArgmnm5UCU triggers the wild-type peptidyl-tRNA to frameshift
Authors: LEIPUVIENE RAMUNE , BJÖRK GLENN R.
Published: April 2005

Frameshift mutations can be suppressed by a variety of differently acting external suppressors. The +1 frameshift mutation hisC3072, which has an extra G in a run of Gs, is corrected by the external suppressor mutation sufF44. We have shown that sufF44 and five additional allelic suppressor mutations are located in the gene argU coding for the minor tRNAArgmnm5UCU and alter the secondary and/or tertiary structure of this tRNA. The C61U, G53A, and C32U mutations influence the stability, whereas the C56U, C61U, G53A, and G39A mutations decrease the arginylation of tRNAArgmnm5UCU. The T-10C mutant has a base substitution in the -10 consensus sequence of the argU promoter that reduces threefold the synthesis of tRNAArgmnm5UCU . The lower amount of tRNAArgmnm5UCU or impaired arginylation, either independently or in conjunction, results in inefficient reading of the cognate AGA codon that, in turn, induces frameshifts. According to the sequence of the peptide produced from the suppressed -GGG-GAA-AGA- frameshift site, the frameshifting tRNA in the argU mutants is tRNAmnm5s2UUCGlu, which decodes the GAA codon located upstream of the AGA arginine codon, and not the mutated tRNAArgmnm5UCU. We propose that an inefficient decoding of the AGA codon by a defective tRNAArgmnm5UCU stalls the ribosome at the A-site codon allowing the wild-type form of peptidyl- tRNAmnm5s2UUCGlu to slip forward 1 nucleotide and thereby re-establish the ribosome in the 0-frame. Similar frame-shifting events could be the main cause of various phenotypes associated with environmental or genetically induced changes in the levels of aminoacylated tRNA.
Policing the Cold War frontier: The Bedford Incident
Authors: Seed David
Published: April 2005

This essay examines the use of the allusions to Moby-Dick in The Bedford Incident (novel 1963; film 1965) in reinforcing its application of the frontier trope, which underpins the description of how a US destroyer hunts a Soviet nuclear submarine in the Denmark Strait.
In particular it focuses on the construction of the Cold War enemy as an unseen alien who, ironically, comes to resemble its American pursuers.