bluuebunny/crossref_metadata_2025 huggingface dataset:
Muscle-specific interaction of caveolin isoforms: differential complex formation between caveolins in fibroblastic vs. muscle cells
Authors: Capozza Franco , Cohen Alex W. , Cheung Michelle W.-C. , Sotgia Federica , Schubert William , Battista Michela , Lee Hyangkyu , Frank Philippe G. , Lisanti Michael P.
Published: November 2004

It is generally well accepted that caveolin-3 expression is muscle specific, whereas caveolin-1 and -2 are coexpressed in a variety of cell types, including adipocytes, endothelial cells, epithelial cells, and fibroblasts. Caveolin-1 and -2 are known to form functional hetero-oligomeric complexes in cells where they are coexpressed, whereas caveolin-3 forms homo-oligomeric high molecular mass complexes. Although caveolin-2 might be expected to interact in a similar manner with caveolin-3, most studies indicate that this is not the case. However, this view has recently been challenged as it has been demonstrated that caveolin-2 and -3 are coexpressed in primary cultures of cardiac myocytes, where these two proteins can be coimmunoprecipitated. Thus it remains controversial whether caveolin-2 interacts with caveolin-3. Here, we directly address the issue of caveolin isoform protein-protein interactions by means of three distinct molecular genetic approaches. First, using caveolin-1-deficient mouse embryonic fibroblasts, in which we have stably expressed caveolin-1, -2, or -3, we find that caveolin-1 interacts with caveolin-2 in this setting, whereas caveolin-3 does not, in agreement with most published observations. Next, we used a transfected L6 myoblast cell system expressing all three caveolin proteins. Surprisingly, we found that caveolin-1, -2, and -3 all coimmunoprecipitate in this cell type, suggesting that this interaction is muscle cell specific. Similar results were obtained when the skeletal muscle of caveolin-1 transgenic animals was analyzed for caveolin-1 and caveolin-3 coimmunoprecipitation. Thus we conclude that all three caveolins can interact to form a discrete hetero-oligomeric complex, but that such complex formation is clearly muscle specific.
Mechanical loading and injury induce human myotubes to release neutrophil chemoattractants
Authors: Tsivitse Susan K. , Mylona Eleni , Peterson Jennifer M. , Gunning William T. , Pizza Francis X.
Published: November 2004

The purpose of this study was to 1) test the hypothesis that skeletal muscle cells (myotubes) after mechanical loading and/or injury are a source of soluble factors that promote neutrophil chemotaxis and superoxide anion (O2−·) production and 2) determine whether mechanical loading and/or injury causes myotubes to release cytokines that are known to influence neutrophil responses [tumor necrosis factor-α (TNF-α), IL-8, and transforming growth factor-β1 (TGF-β1)]. Human myotubes were grown in culture and exposed to either a cyclic strain (0, 5, 10, 20, or 30% strain) or a scrape injury protocol. Protocols of 5, 10, and 20% strain did not cause injury, whereas 30% strain and scrape injury caused a modest and a high degree of injury, respectively. Conditioned media from strained myotubes promoted chemotaxis of human blood neutrophils and primed them for O2−· production in a manner that was dependent on a threshold of strain and independent from injury. Neutrophil chemotaxis, but not priming, progressively increased with higher magnitudes of strain. Conditioned media only from scrape-injured myotubes increased O2−· production from neutrophils. Concentrations of IL-8 and total TGF-β1 in conditioned media were reduced by mechanical loading, whereas TNF-α and active TGF-β1 concentrations were unaffected. In conclusion, skeletal muscle cells after mechanical loading and injury are an important source of soluble factors that differentially influence neutrophil chemotaxis and the stages of neutrophil-derived reactive oxygen species production. Neutrophil responses elicited by mechanical loading, however, did not parallel changes in the release of IL-8, TGF-β1, or TNF-α from skeletal muscle cells.
Role of NBC1 in apical and basolateral HCO3− permeabilities and transendothelial HCO3− fluxes in bovine corneal endothelium
Authors: Li Jinhua , Sun Xing Cai , Bonanno Joseph A.
Published: November 2004

Corneal transparency and hydration control are dependent on HCO3− transport properties of the corneal endothelium. Recent work ( 13 ) suggested the presence of an apical 1Na+-3HCO3− cotransporter (NBC1) in addition to a basolateral 1Na+-2HCO3− cotransporter. We examined whether the NBC1 cotransporter contributes significantly to basolateral or apical HCO3− permeability and whether the cotransporter participates in transendothelial net HCO3− flux in cultured bovine corneal endothelium. NBC1 protein expression was reduced using small interfering RNA (siRNA). Immunoblot analysis showed that 5–15 nM siRNA decreased NBC1 expression by 80–95%, 4 days posttransfection. Apical and basolateral HCO3− permeabilities were determined by measuring the rate of pHi change when HCO3− was removed from the bath under constant pH or constant CO2 conditions. Using either protocol, we found that cultures treated with NBC1 siRNA had sixfold lower basolateral HCO3− permeability than untreated or siCONTROL siRNA-treated cells. Apical HCO3− permeability was unaffected by NBC1 siRNA treatment. Net non-steady-state HCO3− flux was 0.707 ± 0.009 mM·min−1·cm2 in the basolateral-to-apical direction and increased to 1.74 ± 0.15 when cells were stimulated with 2 μM forskolin. Treatment with 5 nM siRNA decreased basolateral-to-apical flux by 67%, whereas apical-to-basolateral flux was unaffected, significantly decreasing net HCO3− flux to 0.236 ± 0.002. NBC1 siRNA treatment or 100 μM ouabain also eliminated steady-state HCO3− flux, as measured by apical compartment alkalinization. Collectively, reduced basolateral HCO3− permeability, basolateral-to-apical fluxes, and net HCO3− flux as a result of reduced expression of NBC1 indicate that NBC1 plays a key role in transendothelial HCO3− flux and is functional only at the basolateral membrane.
Mechanisms Determining the Dynamic Range of the Bullfrog Olfactory Receptor Cell
Authors: Tomaru Akihiro , Kurahashi Takashi
Published: November 2004

Spike discharges of single olfactory receptor cells (ORCs) were recorded with the whole cell patch-clamp method applied to slice preparation. In parallel, activities of transduction channels were measured under the voltage-clamp condition. When cells were stimulated by odorants, 54 out of 306 cells exhibited inward current responses (10 mM cineole in the puffer pipette). The amplitude of the inward current was dependent on the stimulus period, reflecting the time integration for the stimulus dose, and the relation could be fitted by the Hill equation. Under the current-clamp condition, current injection induced spike discharges. In cells showing repetitive firings, the firing frequency was dependent on the amount of injected current. The relation was fitted by the Michaelis-Menten equation showing saturation. When cells were responsive to the odorant and had abilities to discharge repetitive spikes, the depolarizing responses were accompanied by repetitive spikes. In those cells, the spike frequency was dose-dependent, expressing saturation similar to the result obtained by current injection. Since both transduction channel and spike generative steps expressed saturation in their dose dependences, we explored what step(s) actually determines saturation in ORC signaling processes. By examining dose-response relations of both the current and spikes in the same cells, saturating dose was found to be dependent largely on that of the transduction step. This suggests that the dynamic range is fundamentally determined by the transduction system. In addition, a simple model derived from the nonlinearity of the plasma membrane could explain that a critical level of dynamic range was, at least in part, modified by the membrane nonlinearity.
Using Neuronal Latency to Determine Sensory–Motor Processing Pathways in Reaction Time Tasks
Authors: DiCarlo James J. , Maunsell John H. R.
Published: November 2004

We describe a new technique that uses the timing of neuronal and behavioral responses to explore the contributions of individual neurons to specific behaviors. The approach uses both the mean neuronal latency and the trial-by-trial covariance between neuronal latency and behavioral response. Reliable measurements of these values were obtained from single-unit recordings made from anterior inferotemporal (AIT) cortex and the frontal eye fields (FEF) in monkeys while they performed a choice reaction time task. These neurophysiological data show that the responses of AIT neurons and some FEF neurons have little covariance with behavioral response, consistent with a largely “sensory” response. The responses of another group of FEF neurons with longer mean latency covary tightly with behavioral response, consistent with a largely “motor” response. A very small fraction of FEF neurons had responses consistent with an intermediate position in the sensory-motor pathway. These results suggest that this technique is a valuable tool for exploring the functional organization of neuronal circuits that underlie specific behaviors.
Acetylcholine Dynamically Controls Spatial Integration in Marmoset Primary Visual Cortex
Authors: Roberts M. J. , Zinke W. , Guo K. , Robertson R. , McDonald J. S. , Thiele A.
Published: November 2004

Recent in vitro studies have shown that acetylcholine (ACh) selectively reduces the efficacy of lateral cortical connections via a muscarinic mechanism, while boosting the efficacy of thalamocortical/feed-forward connections via a nicotinic mechanism. This suggests that high levels of ACh should reduce center-surround interactions of neurons in primary visual cortex, making cells more reliant on feed-forward information. In line with this hypothesis, we show that local iontophoretic application of ACh in primate primary visual cortex reduced the extent of spatial integration, assessed by recording a neurons' length tuning. When ACh was externally applied, neurons' preferred length shifted toward shorter bars, showing reduced impact of the extra-classical receptive field. We fitted a difference and a ratio of Gaussian model to these data to determine the underlying mechanisms of this dynamic change of spatial integration. These models assume overlapping summation and suppression areas with different widths and gains to be responsible for spatial integration and size tuning. ACh significantly reduced the extent of the summation area, but had no significant effect on the extent of the suppression area. In line with previous studies, we also show that applying ACh enhanced the response in the majority of cells, especially in the later (sustained) part of the response. These findings are similar to effects of attention on neuronal activity. The natural release of ACh is strongly linked with states of arousal and attention. Our results may therefore be relevant to the neurobiological mechanism of attention.
On the Krall‐type polynomials
Authors: Álvarez-Nodarse R. , Arvesú J. , Marcellán F.
Published: November 2004

Using a general and simple algebraic approach, some results on
Krall‐type orthogonal polynomials and some of their extensions
are obtained.
Religious Belief, Scientific Expertise, and Folk Ecology
Authors: Poling Devereaux , Evans E. Margaret
Published: November 2004

In the United States, lay-adults with a range of educational backgrounds often conceptualize species change within a non-Darwinian adaptationist framework, or reject such ideas altogether, opting instead for creationist accounts in which species are viewed as immutable. In this study, such findings were investigated further by examining the relationship between religious belief, scientific expertise, and ecological reasoning in 132 college-educated adults from 6 religious backgrounds in a Midwestern city. Fundamentalist and non-fundamentalist religious beliefs were differentially related to concepts of evolution, adaptation, and extinction. Biological expertise (r = .28) and creationism (r = –.46) were significantly and differentially related to the endorsement of the Darwinian concept of common descent. Yet, creationists were more likely to reject macroevolutionary than microevolutionary concepts. Overall, the greater the taxonomic distance between species, the less likely were participants to agree that species-pairs had common ancestors. It is argued that lay adults from contemporary industrialized societies adopt a view of evolution in which species adapt to novel environments, but remain the same "kind" despite changes. Therefore, extinction is considered unlikely and the relations between micro- and macroevolution misconstrued. Lay-adults' species concepts appear to be an amalgam of a common-sense understanding of species and of evolutionary ideas, modified but not transformed by religious and scientific beliefs. Finally, it is argued that the development of scientific expertise does not involve the radical transformation of ingrained worldviews. Rather, scientists select specializations that are compatible with their existing philosophies, then consciously apply the constructs of their disciplines in order to transcend their common-sense folk beliefs.
I See What You Are Saying: Action as Cognition in fMRI Brain Mapping Practice
Authors: Alač Morana , Hutchins Edwin
Published: November 2004

In cognitive neuroscience, functional magnetic resonance imaging (fMRI) is used to produce images of brain functions. These images play a central role in the practice of neuroscience. In this paper we are interested in how these brain images become understandable and meaningful for scientists. In order to explore this problem we observe how scientists use such semiotic resources as gesture, language, and material structure present in the socially and culturally constituted environment. A micro-analysis of video records of scientists interacting with each other and with fMRI images reveals action as cognition, that is, actions that constitute thinking for the scientists.
Spatial distribution, mobility, gregariousness, and defensive behaviour in a Brazilian cave harvestman Goniosoma albiscriptum (Arachnida, Opiliones, Gonyleptidae)
Authors: Willemart Rodrigo , Gnaspini Pedro
Published: November 2004

This study provides information on population dynamics and behaviour (gregariousness and defensive tactics) of the Brazilian cave harvestman Goniosoma albiscriptum (Goniosomatinae). Through a mark-recapture study, we observed that this species regularly uses the cave during the day, leaving it to forage on the vegetation after dusk (i. e., a trogloxene species). There were nine groups within the cave, composed of females and males, the latter being the only sex that moved from one group to another (although rarely). Distinct groups used distinct openings of the cave to leave the shelter after dusk. Goniosoma albiscriptum showed a variety of mechanical defensive behaviours, and also exuded scent gland secretions. During dryer and colder months (between April and August), adult and subadult harvestmen aggregated on the cave walls. The individuals that composed the aggregations were not always the same ones. Reproductive activity (detected by the presence of egg batches) was negatively correlated with formation of aggregations. We suggest that intolerance towards conspecifics during the reproductive period may inhibit the formation of aggregations.
Study of salinity and temperature tolerance limits regarding four crustacean species in a temporary salt water swamp (Lake Zima, Morocco)
Authors: Rokneddine Aïcha , Chentoufi Mohamed
Published: November 2004

Tolerance boundaries of four crustacean species (Phallocryotus spinosa, Moina salina, Arctodiaptomus salinus and Ctenodaphnia mediterranea) to salinity and temperature were evaluated by studying the species in their natural environment (salted temporary swamp of Lake Zima near Marrakech, Morocco) and in the laboratory. The seasonal density evolution over the year for the four species in their natural environment reveals three phases (youth, maturity and old). The dwell time of each species depends on the environmental factor values as well as on their rate of change. Laboratory study revealed high euryhaline and eurithermal ability for the four species, with a difference in the optimal salinity range from species to species. The ranges are situated between 5 and 25% for C. mediterranea, 15 and 30% for A. salinus, 15 and 60% for M. Salina and 30 and 90% for P. spinosa. Such a range difference, measured under controlled conditions (laboratory), may well explain the variability in the behaviour of the four species in their natural environment. The tolerance range difference from species to species, together with the instability of the environmental conditions of the milieu, seem to be responsible for the quantitative and qualitative changes of the host fauna, which occur within the year and from year to year.
Theorizing the Authentic
Authors: Campbell Kelly B.
Published: November 2004

This article builds upon and extends the work of civic engagement, deliberative democracy, and discourse theorists by critically examining the ways in which civic engagement is currently conceptualized and utilized. Through this analysis, critical oversights, assumptions, and biases concerning the potential of public participation, the nature of who is or is not engaged, and the places where authentic engagement is occurring are revealed. To move the field forward and to prevent scholars and practitioners from inadvertently sustaining the very problems they are attempting to rectify, this author posits that a more critical and reflective approach to civic engagement and public participation efforts is needed. The article concludes with suggestions for alternative locations of engagement, future research, and public administration’s role in supporting and facilitating publicly engaged citizens.
Setting the Stage
Authors: Hajer Maarten A.
Published: November 2004

This article aims to shed light on the performative dimension of participation in policy making. It is argued that we can enhance our understanding of the dynamics of policy deliberation examining the setting in which the deliberation takes place as well as the particular staging of that setting. Portraying political processes as sequences of staged performances of conflict and conflict resolution, this article analyzes how the design of the setting affects what is said, what can be said, and what can be said with influence. This helps to understand why many of the familiar participatory arrangements fail to satisfy both governments and the public. It also gives a new perspective on joint policy learning and opens a perspective on how to enhance the democratic quality of policy deliberation.
The Rhetoric of Management Control in Italian Cities
Authors: Battistelli Fabrizio , Ricotta Giuseppe
Published: November 2004

This article deals with Italian administrative change. The introduction of management control and evaluation systems in Italian local governments is the best example of the managerial rhetoric of administrative change in Italy. Actually, it brings new meanings of public action and suggests new identities taken from the private sphere. The authors point out some critical aspects of this local governments reform in the frame of the neo-liberal ideology. Particularly, the reductive codification of the concept of effectiveness, which the reform laws describe as a verification of organizational output, supports an auto-referential system of control and evaluation.
Innovative Analyses and Interventions in the Treatment of Selective Mutism
Authors: Jackson Melissa F. , Allen Rebecca S. , Boothe Allison B. , Nava Marisa L. , Coates Adriana
Published: November 2004

The authors present a successful, 25-session, multidimensional intervention for the treatment of selectivemutismin a 6-year-old male with a 1-year observational follow-up. They also include an evaluative review of the extant literature of the treatment of selective mutism from 1950 to the present. Their assessment approach utilized behavioral, cognitive, systems, and psychodynamic components. Treatment efficacy was assessed through videotaped observation of behavioral time-samples of the client during therapeutic interaction, self-report, parental report, and real-time behavioral observations at school. Results indicated a significant increase in verbal behaviors during therapy sessions, paired t(17) = 2.31, p= .033. In addition, the client was observed to be verbally interacting with peers and teachers at school at 1-year follow-up. These results suggest that the authors’ multidimensional approach to the treatment of selectivemutismmay offer a successful, brief intervention for those families in which parents decline use of pharmacotherapy in a child.
AIDS-defining illnesses among patients with HIV in Singapore, 1985 to 2001: results from the Singapore HIV Observational Cohort Study (SHOCS)
Authors: Bellamy Richard , Sangeetha S , Paton Nicholas I
Published: November 2004

Background

The objective was to describe the causes of initial and overall AIDS-defining disease episodes among HIV patients in Singapore.

Methods

A retrospective observational cohort study was performed of all adult patients seen at the national HIV referral center between 1985 and 2001. Data were extracted from the patients' records by ten trained healthcare workers. AIDS-defining conditions were established using predefined criteria.

Results

Among 1504 patients, 834 had experienced one or more AIDS-defining diseases. The most frequent causes of the initial AIDS-defining episode were Pneumocystis carinii pneumonia (35.7%), Mycobacterium tuberculosis (22.7%) and herpes simplex (7.4%). In total 1742 AIDS-defining episodes occurred. The most frequent causes were Pneumocystis carinii pneumonia (25.1%), Mycobacterium tuberculosis (16.2%) and cytomegalovirus retinitis (9.5%).

Conclusions

The most frequent causes of AIDS-defining illnesses in Singapore are similar to those reported in the West, prior to the introduction of anti-retroviral therapy. Opportunistic infections remain the most frequent AIDS-defining illnesses.
Reduction in CD1d expression on dendritic cells and macrophages by an acute virus infection
Authors: Lin Yinling , Roberts Tonya J , Spence Philip M , Brutkiewicz Randy R
Published: November 2004

Mice were infected with lymphocytic choriomeningitis virus (LCMV) to determine if changes in CD1d expression occurred during an acute virus infection. It is interesting that a decrease in CD1d expression on splenic dendritic cells (DC) and macrophages (MΦ) was observed for at least 3 months post-LCMV infection, and vaccinia virus and vesicular stomatitis virus induced similar changes in CD1d upon infection with those viruses. The reduction of CD1d cell-surface expression on DC and MΦ was independent of interferon-γ and interleukin-12 expression but partially recovered in transporter associated with antigen processing-1-deficient mice, suggesting that CD8+ T cells may play a role. Thus, one consequence of the induction of a cellular immune response is a change in CD1d expression, which may constitute a key element in regulating antiviral immunity.
The effect of quercetin on the pharmacokinetics of verapamil and its major metabolite, norverapamil, in rabbits
Authors: Choi Jun-Shik , Han Hyo-Kyug
Published: November 2004

We have investigated the effect of quercetin on the pharmacokinetics of verapamil and its major metabolite, norverapamil, in rabbits. Pharmacokinetic parameters of verapamil and norverapamil were determined after the oral administration of verapamil (10 mg kg−1) to rabbits in the presence and absence of quercetin (5.0 and 15 mg kg−1). While co-administration of quercetin concurrently was not effective to enhance the oral exposure of verapamil, pretreatment of quercetin 30 min before verapamil administration significantly altered the pharmacokinetics of verapamil. Compared with the control group (given verapamil alone), the Cmax and AUC of verapamil increased approximately twofold in the rabbits pretreated with 15 mg kg−1 quercetin. There was no significant change in Tmax and terminal plasma half-life (t½) of verapamil in the presence of quercetin. Consequently, absolute and relative bioavailability values of verapamil in the rabbits pretreated with quercetin were significantly higher (P<0.05) than those from the control group. Metabolite-parent AUC ratio in the rabbits pretreated with quercetin decreased by twofold compared with the control group, implying that pretreatment of quercetin could be effective to inhibit the CYP3A4-mediated metabolism of verapamil. In conclusion, pretreatment of quercetin significantly enhanced the oral exposure of verapamil. This suggested that concomitant use of quercetin or a quercetin-containing dietary supplement with verapamil requires close monitoring for potential drug interaction.
Does the well-stirred model assess the intestinal first-pass effect well?
Authors: Mizuma Takashi , Tsuji Akira , Hayashi Masahiro
Published: November 2004

The pre-systemic intestinal extraction ratio (Eg) has been estimated by an equation based on the well-stirred model, which does not have a term of membrane transport. In this report, we have identified the application limitations of the well-stirred model equation to assess the pre-systemic intestinal extraction ratio. The Eg of metoprolol (CYP2D6 substrate) was assessed by three methods. Intrinsic clearances for metoprolol metabolism in hepatic and gastrointestinal microsomes were from a published report. Method 1 (model-independent method): the Eg of 0.228 was obtained according to the equation, F = Ff × (1 — Eg) × Fh, where F, Ff and Fh were the bioavailability, the fraction entering the intestinal tissue and the hepatic availability, respectively. Method 2: the Eg of 0.0071 was calculated according to the well-stirred model equation, and was much lower than the value of 0.228. Method 3: the Eg of 0.213 was obtained by the transport-metabolism-flow (TMF) model equation, and was much closer to the value of 0.228 obtained by the model-independent method than the Eg of 0.0071 calculated by the well-stirred model equation. Therefore, we propose that the factor of membrane transport process be incorporated into the pharmacokinetic model for the assessment of the pre-systemic intestinal extraction ratio.
The antioxidative effect of icariin in human erythrocytes against free-radical-induced haemolysis
Authors: Liu Zai-Qun , Luo Xu-Yang , Sun Yun-Xiu , Wu Wei , Liu Chun-Ming , Liu Zhi-Qiang , Liu Shu-Ying
Published: November 2004

Icariin (2-(4′-methoxyl phenyl)-3-rhamnosido-5-hydroxyl-7-glucosido-8-(3′-methyl-2-butylenyl)-4-chromanone) is the major component in Herba Epimedii used in traditional Chinese medicine for the treatment of atherosclerosis. This work focuses on the antioxidative effect of icariin on free-radical-induced haemolysis of human erythrocytes, in which the initial free radical derives from the decomposition of 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH) at physiological temperature. To reveal the structure-activity relationship of icariin, the antioxidant effects of two structural analogues of icariin, acacetin (2-(4′-methoxylphenyl)-5,7-dihydroxylchromone) and norwogonin (2-phenyl-5,7,8-trihydroxylchromone), on the same experimental system were examined as well. It was found that all these chromone derivatives (Chm-OHs) dose-dependently protected human erythrocytes against free-radical-induced haemolysis. The order of antioxidative activity was norwogonin>acacetin>icariin by the analysis of the relationship between the concentration of Chm-OHs and the prolongation percentage of the lag time of haemolysis (PP%). It was also proved that the phenyl hydroxyl group attached to the chromone ring at 7-position cannot trap the free radical. On the contrary, phenyl hydroxyl groups at the 5- and 8-position in norwogonin made it a significant antioxidant in AAPH-induced haemolysis. The more hydroxyl groups attached to the chromone ring, the higher the antioxidative activity in protecting erythrocytes against free-radical-induced peroxidation.
Determination of diffusion coefficients of peptides and prediction of permeability through a porous membrane
Authors: Hosoya Osamu , Chono Sumio , Saso Yuko , Juni Kazuhiko , Morimoto Kazuhiro , Seki Toshinobu
Published: November 2004

The diffusion coefficient (D) of peptide and protein drugs needs to be determined to examine the permeability through biological barriers and to optimize delivery systems. In this study, the D values of fluorescein isothiocyanate (FITC)-labelled dextrans (FDs) and peptides were determined and the permeability through a porous membrane was discussed. The observed D values of FDs and peptides, except in the case of insulin, were similar to those calculated based on a relationship previously reported between the molecular weight and D of lower-molecular-weight compounds, although the molecular weight range was completely different. The observed D value of insulin was between the calculated values for the insulin monomer and hexamer. The permeability of poly-lysine and insulin through the membrane was determined and the observed values were compared with predicted values by using the relationship between molecular weight and D and an equation based on the Renkin function. The observed permeability of insulin through the membrane was between that of the predicted permeability for the insulin monomer and hexamer. For the permeation of insulin, the determination of D was useful for estimating the permeability because of the irregular relationship between molecular weight and D. The methodology used in this study will be useful for a more quantitative evaluation of the absorption of peptide and protein drugs applied to mucous membranes.
Pharmacokinetics of intravenous and oral DA-8159, a new erectogenic, in rats with protein-calorie malnutrition
Authors: Shim Hyun J , Kim Yu C , Lee Joo H , Ahn Byung O , Kwon Jong W , Kim Won B , Lee Inchul , Lee Myung G
Published: November 2004

Influence of dietary protein deficiency on the pharmacokinetics of DA-8159 and one of its metabolites, DA-8164, was investigated after intravenous and oral administration of DA-8159 at a dose of 30 mg kg−1 to male Sprague-Dawley rats allowed free access to a 23% (control) or 5% (protein-calorie malnutrition, PCM) casein diet for 4 weeks. The total area under the plasma concentration-time curve from time zero to time infinity (AUC) values of DA-8164 were significantly smaller after both intravenous (87.0 vs 162 μg min mL−1) and oral (144 vs 319 μg min mL−1) administration of DA-8159 to PCM rats. This could be due to the decrease in CYP3A1/2 (50–60%) in the rats because DA-8164 was mainly formed via CYP3A1/ 2 in rats. This could be supported by significantly slower in-vitro CLint (2.04 ± 0.646 vs 3.15 ± 0.693 μL min−1 (mg protein)−1) for the formation of DA-8164 in hepatic microsomal fraction of PCM rats. After intravenous administration of DA-8159, the AUC values of DA-8159 were not significantly different between the two groups of rats although the AUC of DA-8164 was significantly smaller in PCM rats, and this may be due to the minor metabolic pathway of DA-8164 in rats. However, after oral administration of DA-8159, the AUC of DA-8159 was significantly greater in PCM rats (194 vs 122 μg min mL−1). This was not due to enhanced absorption of DA-8159 from the gastrointestinal tract in the rats but may be due to a decreased intestinal first-pass effect of DA-8159 in the rat.
Novel thiocyanato complexes with potent cytotoxic and antimicrobial properties
Authors: Hossain M Shamim , Easmin Sabina , Islam M Saidul , Rashid Mamunur
Published: November 2004

The aim of the present study was to assess the cytotoxic and antimicrobial properties of seven new thiocyanato complexes: Ni(C9H11N2O)(SCN), Cu(C9H11N2O)(SCN), Pd(C9H11N2O)(SCN), Pt(C9H11N2O) (SCN), K[Ti(C9H11N2O)(SCN)3], Au(C9H11N2O)(SCN), and K[V(O)(C9H11N2O)(SCN)] (T1-T7, respectively). All the complexes showed toxicity against brine shrimp nauplii (Artemia salina L.). The titanium-based complex, T5, exhibited potent toxicity, with a lethal concentration 50% (the concentration of test compound that kills 50% of A. salina) value of 1.59 μg mL−1. These new complexes also exhibited promising antibacterial and antifungal properties. A macrodilution technique was used to estimate the minimum inhibitory concentrations of the seven bioactive complexes. Minimum inhibitory concentrations were found to be 8–64 μg mL−1 against the tested bacterial species.
Enhancement of natural killer cell activity of aged mice by modified arabinoxylan rice bran (MGN-3/Biobran)
Authors: Ghoneum Mamdooh , Abedi Sarah
Published: November 2004

The present study is aimed to examine the possibility of enhancement of natural killer (NK) cell activity in aged C57BL/6 and C3H mice using MGN-3, a modified arabinoxylan from rice bran. Intraperitoneal injection of MGN-3 (10 mg kg−1 per day) caused a remarkable increase in the peritoneal NK activity as early as 2 days (35.2 lytic units), and the level remained elevated through day 14. The control aged mice had a level of 5.8 lytic units. Enhancement in NK activity was associated with an increase in both the binding capacity of NK cells to tumour targets and in the granular content as measured by BLT-esterase activity. Treatment did not alter the percentage of peritoneal NK cells. Data showed that peritoneal macrophages inhibit NK activity. In conclusion, MGN-3 enhances murine NK activity of aged mice and may be useful for enhancing NK function in aged humans.
Solid lipid nanoparticles (SLNs) to improve oral bioavailability of poorly soluble drugs
Authors: Hu LianDong , Tang Xing , Cui FuDe
Published: November 2004

The purpose of this work was to improve the oral bioavailability of poorly soluble drugs by incorporation into solid lipid nanoparticles (SLNs). All-trans retinoic acid (ATRA) was used as a poorly soluble model drug. Different formulations of SLNs loaded with ATRA were successfully prepared by a high-pressure homogenization method and using Compritol 888 ATO as lipid matrix. The particle size and distribution, drug loading capacity, drug entrapment efficiency (EE %), zeta potential, and long-term physical stability of the SLNs were investigated in detail. Drug release from two sorts of ATRA-SLN was studied and compared with the diffusion from ATRA solution in 0.1 M HCl, distilled water and phosphate buffer (pH 7.40), using a dialysis bag method. A pharmacokinetic study was conducted in male rats after oral administration of 8 mg kg−1 ATRA in different formulations and it was found that the relative bioavailability of ATRA in SLNs was significantly increased compared with that of an ATRA solution. The amount of surfactant also had a marked effect on the oral absorption of ATRA with SLN formulations. Although an emulsion formulation also increased ATRA absorption, it was too unstable for use in clinical situations. The absorption mechanism of the SLN formulations was discussed. These results indicate that ATRA absorption is enhanced significantly by employing SLN formulations. SLNs offer a new approach to improve the oral bioavailability of poorly soluble drugs.
Natural phenylpropanoids inhibit lipoprotein-induced endothelin-1 secretion by endothelial cells
Authors: Martin-Nizard Françoise , Sahpaz Sevser , Kandoussi Abdelmejid , Carpentier Marie , Fruchart Jean-Charles , Duriez Patrick , Bailleul François
Published: November 2004

There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherosclerosis. Endothelin-1 (ET-1) is a potent vasoconstrictor peptide isolated from endothelial cells and it induces smooth muscle cell proliferation. ET-1 secretion is increased in atheroma and induces deleterious effects such as vasospasm and atherosclerosis. The goal of this study was to test the effect of four natural phenolic compounds against copper-oxidized LDL (Cu-LDL)-induced ET-1 liberation by bovine aortic endothelial cells (BAEC). The tested compounds were phenylpropanoid glycosides previously isolated from the aerial parts of Marrubium vulgare L. (acteoside 1, forsythoside B 2, arenarioside 3 and ballotetroside 4). ET-1 secretion increased when cells were incubated with Cu-LDL but the compounds 1–4 inhibited this increase. These results were confirmed by quantitative-polymerase chain reaction (QPCR) analysis. Since ET-1 plays an important role in atherosclerosis development, our work suggests that the tested phenylpropanoids could have a beneficial effect in inhibiting atherosclerosis development.
Defective paracrine signalling by TGFβ in yolk sac vasculature of endoglin mutant mice: a paradigm for hereditary haemorrhagic telangiectasia
Authors: Carvalho Rita L. C. , Jonker Leon , Goumans Marie-José , Larsson Jonas , Bouwman Peter , Karlsson Stefan , Dijke Peter ten , Arthur Helen M. , Mummery Christine L.
Published: November 2004

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder in humans that is characterised by multisystemic vascular dyplasia and recurrent haemorrhage. Germline mutations in one of two different genes,endoglin or ALK1 can cause HHT. Both are members of the transforming growth factor (TGF) β receptor family of proteins, and are expressed primarily on the surface of endothelial cells (ECs). Mice that lack endoglin or activin receptor like kinase (ALK) 1 die at mid-gestation as a result of defects in the yolk sac vasculature. Here, we have analyzed TGFβsignalling in yolk sacs from endoglin knockout mice and from mice with endothelial-specific deletion of the TGFβ type II receptor (TβRII)or ALK5. We show that TGFβ/ALK5 signalling from endothelial cells to adjacent mesothelial cells is defective in these mice, as evidenced by reduced phosphorylation of Smad2. This results in the failure of vascular smooth muscle cells to differentiate and associate with endothelial cells so that blood vessels remain fragile and become dilated. Phosphorylation of Smad2 and differentiation of smooth muscle can be rescued by culture of the yolk sac with exogenous TGFβ1. Our data show that disruption of TGFβsignalling in vascular endothelial cells results in reduced availability of TGFβ1 protein to promote recruitment and differentiation of smooth muscle cells, and provide a possible explanation for weak vessel walls associated with HHT.
Kaiso is a genome-wide repressor of transcription that is essential for amphibian development
Authors: Ruzov Alexey , Dunican Donncha S. , Prokhortchouk Anna , Pennings Sari , Stancheva Irina , Prokhortchouk Egor , Meehan Richard R.
Published: November 2004

DNA methylation in animals is thought to repress transcription via methyl-CpG specific binding proteins, which recruit enzymatic machinery promoting the formation of inactive chromatin at targeted loci. Loss of DNA methylation can result in the activation of normally silent genes during mouse and amphibian development. Paradoxically, global changes in gene expression have not been observed in mice that are null for the methyl-CpG specific repressors MeCP2, MBD1 or MBD2. Here, we demonstrate that xKaiso, a novel methyl-CpG specific repressor protein, is required to maintain transcription silencing during early Xenopus laevis development. In the absence of xKaiso function, premature zygotic gene expression occurs before the mid-blastula transition (MBT). Subsequent phenotypes(developmental arrest and apoptosis) strongly resemble those observed for hypomethylated embryos. Injection of wild-type human kaiso mRNA can rescue the phenotype and associated gene expression changes of xKaiso-depleted embryos. Our results, including gene expression profiling, are consistent with an essential role for xKaiso as a global repressor of methylated genes during early vertebrate development.
Green-coloured results on guaiac-based faecal occult blood testing should be considered positive
Authors: Gordon Joy C , Steele RJC , Fraser CG
Published: November 2004

Background: In guaiac-based faecal occult blood tests (FOBT), blue colours are considered positive. Blue-green colours should also be considered positive. Distinct green colours are said to be due to bile and it is stated that these should be interpreted as negative. The purpose of this study was to determine the clinical outcomes in individuals in whom the FOBT had difficult-to-interpret green colours that did not wash out on addition of developer.

Methods: During the examination of 134 844 FOBT received in the Scottish laboratory in the first screening round of the UK Colorectal Cancer Screening Pilot, samples with green colour that did not wash out during development were identified. The clinical outcomes were determined from the comprehensive data set collected for each participant.

Results: A small number (77) of FOBT were recorded as green-coloured on development. These were reported as positive and the usual investigation algorithm followed. Significant pathology was present in 31 of the 77 participants (40.3%). Negative outcomes encompassed 39 of the 77 participants (50.6%). The outcome could not be determined accurately for seven of the 77 participants (9.1%). Importantly, 17 of the participants (22.1%) had polyps.

Conclusions: Any green colour that does not wash out to the periphery of the guaiac tape on development of FOBT should be reported as a positive result, and manufacturers should clarify their instructions on interpretation.
Clinical and laboratory features of calcium-sensing receptor disorders: a systematic review
Authors: Gunn Ian R , Gaffney Dairena
Published: November 2004

Mutations in the calcium-sensing receptor gene ( CaSR) may result in disorders of calcium homeostasis manifesting as familial benign hypocalciuric hypercalcaemia (FBHH), neonatal severe hyperparathyroidism (NSHPT) or autosomal dominant hypocalcaemia with hypercalciuria (ADHH). FBHH may have a population prevalence as high as one in 16 000, and ADHH one in 70 000. NSHPT is very rare.

The FBHH condition is usually asymptomatic. Parathyroidectomy does not result in normal serum calcium, and no active treatment is indicated. To differentiate FBHH from primary hyperparathyroidism (PHPT), a guideline which includes measurement of serum calcium, intact parathyroid hormone (PTH), magnesium and fasting urinary calcium excretion is proposed. Screening of family members for hypercalcaemia, and occasionally a search for mutations in the CaSR gene, may be required.

The NSHPT condition may manifest with hypercalcaemia, (usually) very elevated serum PTH concentration, subperiosteal erosions and fractures. Milder cases may be managed medically, but respiratory failure, extreme hypercalcaemia and failure to thrive are indications for early parathyroidectomy.

The ADHH condition may result in asymptomatic hypocalcaemia, but some affected family members have minor symptoms, and a minority experience seizures in infancy which can recur into adulthood. A significant proportion of cases previously reported as idiopathic hypoparathyroidism (IHP) may in fact be due to mutations in the CaSR gene. In a moderately hypocalcaemic patient with no other clearly discernible cause, an elevated urine calcium:creatinine ratio is suggestive of ADHH, as is the presence of a first-degree relative with hypocalcaemia. If treatment with vitamin D analogues is undertaken, serum and urine calcium should be monitored, advice which applies equally to ADHH and IHP.
Bilateral adrenal enlargement and non-suppressible hypercortisolism as a presenting feature of gastric cancer
Authors: Biswas M , Smith JC , Davies JS
Published: November 2004

In patients with cancer, adrenal enlargement due to either metastatic disease or diffuse non-metastatic hyperplasia is increasingly recognized with modern imaging techniques. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, characterized by non-suppressible hypercortisolism, has also been described in neoplasia in the absence of ectopic adrenocorticotrophic hormone (ACTH) production.

In the majority of cases of malignancy-associated hypercortisolism, it might be expected that the presence of malignant disease would be clinically apparent, thus rendering a detailed endocrinological evaluation of the HPA axis unnecessary. However, in the present case we describe a patient with occult malignancy presenting with bilateral adrenocortical enlargement and non-suppressible hypercortisolism that was not due to the ectopic ACTH syndrome. There were no clinical Cushingoid features other than hypertension and new-onset diabetes mellitus. Detailed diagnostic investigations for the possibility of Cushing's syndrome were performed before the underlying diagnosis of gastric adenocarcinoma eventually became apparent. Characteristics and potential mechanisms of non-suppressible hypercortisolism in cancer are discussed.

We believe that this scenario will occur with greater frequency in the future, given the increasing early use of sophisticated high-resolution imaging for the evaluation of suspected intra-abdominal pathology.
Plasma fibrinogen
Authors: Lowe Gordon DO , Rumley Ann , Mackie Ian J
Published: November 2004

Fibrinogen is the major plasma protein coagulation factor. Low plasma fibrinogen concentrations are therefore associated with an increased risk of bleeding due to impaired primary and secondary haemostasis. Fibrinogen is a classical positive acute-phase reactant protein and is an independent predictor of coronary heart disease events. This review considers available methods for measurement of fibrinogen and makes recommendations as to their appropriate use.

Total clottable fibrinogen assays are the definitive and reference method for plasma fibrinogen measurement. However, they are time-consuming and are rarely required in clinical practice. Clotting rate assays remain the routine method of choice for investigation, monitoring and treatment of bleeding disorders associated with low plasma fibrinogen concentrations. They are appropriately sited in haematology or haemostasis laboratories, with facilities for further relevant investigations, and expert advice from consultant haematologists on appropriate management. They have also been used in the majority of studies investigating increasing fibrinogen concentrations as a cardiovascular risk factor. Prothrombin-time derived assays are widely used, because they are less expensive and come at no extra cost with prothrombin time assays. However, their results vary widely with analysers and reagents, show discrepancies with clotting rate assays for both low and normal plasma fibrinogen samples, and at present they are not recommended by routine clinical use. Immunoassays (radial immunodiffusion, enzyme-linked immunosorbent assay or nephelometric) are useful in (a) differentiating hypofibrinogenaemia from dysfibrinogenaemia, and (b) assessing cardiovascular risk and acute-phase reactions. Unlike clottable fibrinogen assays, immunoassays can be performed in dipotassium edetate anticoagulated samples.