bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intestinal Brush-border Membrane Transport of Monocarboxylic Acids Mediated by Proton-coupled Transport and Anion Antiport Mechanisms
Authors: Tamai Ikumi , Takanaga Hitomi , Maeda Hiroshi , Yabuuchi Hikaru , Sai Yoshimichi , Suzuki Yuichi , Tsuji Akira 
Published: April 2011

Abstract
Intestinal brush-border membrane transport of monocarboxylic acids was investigated by using rabbit intestinal brush-border membrane vesicles (BBMVs) and isolated intestinal tissues mounted on Ussing-type chambers.
[3H]Mevalonic acid uptake by BBMVs showed an overshoot phenomenon in the presence of an inwardly directed proton gradient, but not in the presence of an inwardly directed sodium gradient or an outwardly directed HCO3− or chloride gradient. Initial uptake of mevalonic acid was saturable in the presence of a proton gradient. Uptake of [3H]mevalonic acid was inhibited by various monocarboxylic acids, including acetic acid, benzoic acid, lactic acid, nicotinic acid, pravastatin, salicylic acid and valproic acid, but not by dicarboxylic acid or amino acids. Acetic acid, which is transported by both anion antiport and proton-coupled transport systems, induced serosal bicarbonate-dependent alkalinization in the mucosal-side bathing solution of rabbit jejunal tissues, when examined in Ussing-type chambers. Pravastatin, which is a structural analogue of mevalonic acid and is absorbed via proton-coupled transport like mevalonic acid, did not. The result demonstrates that acetic acid is transported by the bicarbonate-dependent anion antiport system, whereas pravastatin is not.
So, it is suggested that monocarboxylic acids are transported by at least two independent transporters, namely, a proton-coupled transporter for most monocarboxylic acids, including mevalonic acid, pravastatin and acetic acid, and an anion antiporter for acetic acid, but not for mevalonic acid or pravastatin. Activation of anion antiporter can induce HCO3− secretion in intact intestine.
Pharmacological Activity of Feverfew (Tanacetum parthenium (L.) Schultz-Bip.): Assessment by Inhibition of Human Polymorphonuclear Leukocyte Chemiluminescence In-vitro
Authors: Brown Andrew M G , Edwards Carl M , Davey Michael R , Power J Brian , Lowe Kenneth C 
Published: April 2011

Abstract
The bioactivity of feverfew (Tanacetum parthenium) leaf extracts has been analysed, by use of a human polymorphonuclear leukocyte (PMNL) bioassay, to assess the relative contributions of solvent extraction and parthenolide content to the biological potency of the extract.
Extracts prepared in acetone-ethanol (system 1) contained significantly more parthenolide (mean ± s.d. 1.3 ± 0.2% dry leaf weight) than extracts in chloroform–PBS (phosphate-buffered saline; system 2; 0.1 ± 0.04% dry leaf weight) or PBS alone (system 3; 0.5 ± 0.1% dry leaf weight). Extract bioactivity, measured as inhibition of phorbol 12-myristate 13-acetate-induced, 5-amino-2,3-dihydro-1,4-phthalazinedione (luminol)-enhanced PMNL chemiluminescence, followed a similar trend. Extracts inhibited phorbol 12-myristate 13-acetate-induced oxidative burst by amounts which, if solely attributable to parthenolide, indicated parthenolide concentrations for the respective solvent systems of 2.2 ± 0.6%, 0.2 ± 0.1% and 0.9 ± 0.1% dry leaf weight. The mean ratio of parthenolide concentration to the parthenolide equivalent/PMNl-bioactivity value, for acetone–ethanol and PBS extracts were both 1:1.7.
Parthenolide, although a key determinant of biological activity for T. parthenium leaf extracts based on the PMNl-bioassay, seems not to be the sole pharmacologically-active constituent. The identical and elevated bioactivity-parthenolide ratios for both organic and aqueous-phase leaf extracts suggest that a proportion of the other bioactive compounds have solubilities similar to that of parthenolide.
Studies on Amidated Pectins as Potential Carriers in Colonic Drug Delivery
Authors: Wakerly Zoë , Fell John , Attwood David , Parkins David 
Published: April 2011

Abstract
Amidated pectins have been assessed, in-vitro, for their potential value in colonic drug delivery. The monitoring of the release of a model soluble drug, paracetamol, gives a sensitive indication of the behaviour of the pectins under simulated gastrointestinal conditions.
Inclusion of calcium as a cross-linking agent increased the viscosities of amidated pectin gels to a maximum value. Further addition of calcium reduced gel viscosity and for pectin with a high extent of amidation this led to a reduction in drug release. Release was faster for pectin with less amidation in the presence of calcium; this could be related to matrix erosion.
The results of the study suggest that the materials might be of value in colonic delivery either alone or in combination, possibly in the form of a coating.
Possible Involvement of Protein Kinase C Inhibition in The Reduction of Phorbol Ester-induced Neutrophil Aggregation by Magnolol in the Rat
Authors: Wang Jih P , Lin Pei L , Hsu Mei F , Chen Chien C 
Published: April 2011

Abstract
The influence of the plant product magnolol on neutrophil aggregation has been investigated in the rat.
Magnolol inhibited phorbol 12-myristate 13-acetate (PMA)-activated rat neutrophil aggregation in a concentration-dependent manner with an IC50 (concentration resulting in 50% inhibition) of 24.2 ± 1.7 μM. Magnolol suppressed the enzyme activity of neutrophil cytosolic and rat brain protein kinase C (PKC) over the same range of concentrations at which it inhibited the aggregation. Magnolol did not affect PMA-induced cytosolic PKC-α and -δ membrane translocation or trypsin-treated rat-brain PKC activity, but attenuated [3H]phorbol 12,13-dibutyrate binding to neutrophil cytosolic PKC.
These results suggest that the inhibition of PMA-induced rat neutrophil aggregation by magnolol is probably attributable, at least in part, to the direct suppression of PKC activity through blockade of the regulatory region of PKC.
Interspecies Scaling: Predicting Volumes, Mean Residence Time and Elimination Half-life. Some Suggestions
Authors: Mahmood Iftekhar 
Published: April 2011

Abstract
Extrapolation of animal data to assess pharmacokinetic parameters in man is an important tool in drug development. Clearance, volume of distribution and elimination half-life are the three most frequently extrapolated pharmacokinetic parameters. Extensive work has been done to improve the predictive performance of allometric scaling for clearance. In general there is good correlation between body weight and volume, hence volume in man can be predicted with reasonable accuracy from animal data. Besides the volume of distribution in the central compartment (Vc), two other volume terms, the volume of distribution by area (Vβ) and the volume of distribution at steady state (Vdss), are also extrapolated from animals to man. This report compares the predictive performance of allometric scaling for Vc, Vβ and Vdss in man from animal data.
The relationship between elimination half-life (t 1/2) and body weight across species results in poor correlation, most probably because of the hybrid nature of this parameter. To predict half-life in man from animal data, an indirect method (CL = VK, where CL = clearance, V is volume and K is elimination rate constant) has been proposed. This report proposes another indirect method which uses the mean residence time (MRT). After establishing that MRT can be predicted across species, it was used to predict half-life using the equation MRT= 1.44 x t 1/2.
The results of the study indicate that Vc is predicted more accurately than Vβ and Vdss in man. It should be emphasized that for first-time dosing in man, Vc is a more important pharmacokinetic parameter than Vβ or Vdss. Furthermore, MRT can be predicted reasonably well for man and can be used for prediction of half-life.
Influence of Interfacial Rheological Properties of Mixed Emulsifier Films on the Stability of Water-in-Oil-in-Water Emulsions
Authors: Opawale Foyeke O , Burgess Diane J 
Published: April 2011

Abstract
The purpose of this study was to investigate the influence of mixtures of the emulsifiers Span 80, 83 and 85 and Tween 80 on multiple emulsion stability. An oscillatory ring-surface rheometer was used to measure interfacial elasticity at the oil-aqueous interface. Multiple emulsions were prepared via a two-step emulsification process and stability was evaluated by investigation of drug transport from freshly prepared and eight-day-old emulsions by use of a dialysis method. Photomicrography and droplet-size analysis of multiple emulsions were also conducted.
Spans 80 and 83 were appreciably elastic (683.10 ± 29.13 mNm−1 and 1128.09 ± 14.81 mNm−1, respectively at 5% w/v) when present at the mineral oil-aqueous interface whereas Span 85 and Tween 80 were not (11.10 ± 3.88 mNm−1 (5% w/v) and 0 (0.1–5% w/v) respectively). The interfacial elasticities of Spans 80 and 83 decreased in the presence of Tween 80 in the aqueous phase; this was attributed to co-adsorption of Tween 80 at the interface or aqueous-phase solubilization of the Spans within mixed micelles, or both. Drug-transport studies indicated that drug release on storage was lower from water-in-oil-in-water (w/o/w) emulsions prepared with 5% w/v Span 80 or 83 and 0.1% w/v Tween 80 than from emulsions prepared with 5% w/v Spans 80 or 83 and 1% w/v Tween 80. Photomicrography and droplet-size analysis indicated the same trend—emulsions containing a higher percentage of Tween 80 were less stable. The relatively stable w/o/w emulsions (e.g. 5% w/v Spans 80 or 83 and 0.1% w/v Tween 80) contained a large number of multiple droplets for up to eight weeks of storage whereas the relatively unstable w/o/w emulsions (e.g., 5% w/v Span 85 and 0.1% w/v Tween 80 and 5% w/v Spans and 1% w/v Tween 80) contained mostly simple droplets after only one week of storage. The mean volume/weight droplet size decreased on storage with breakdown of these w/o/w emulsions to simple oil-in-water emulsions.
There was a positive correlation between the interfacial elasticity and emulsion stability data. Mixed emulsifiers giving higher film strength, as quantified by interfacial elasticity measurements, resulted in more stable w/o/w emulsions.
Uptake of Fluoroquinolones in Human Monocytes Isolated from Peripheral Blood
Authors: Dorian Martine , Grellet Jean , Saux Marie C 
Published: April 2011

Abstract
The aim of this study was to develop a technique for separating monocytic cells in suspension from peripheral blood to measure the intracellular penetration of three fluoroquinolones (ofloxacin, ciprofloxacin and sparfloxacin).
Mononucleated cells were isolated from the blood on a density gradient with lymphoprep and purified by a specific technique of adhesion and disadhesion on fibronectin. The monocytes were obtained in suspension with 76.8% purity and 97.9% viability. This was a convenient form for measurement of intracellular accumulation by use of the velocity-centrifugation technique. Intra-monocytic penetration of ciprofloxacin, ofloxacin and sparfloxacin was measured at equilibrium after 30-min incubation in the presence of 16 μg mL−1 antibiotic. The results revealed low intra-monocytic accumulation of ciprofloxacin (intracellular-extracellular = 1.76) and ofloxacin (intracellular-extracellular = 1.42). The penetration of sparfloxacin was significantly higher (intracellular-extracellular = 2.4).
This study confirms the important differences between human immunocompetent cells in terms of their ability to concentrate quinolones. It also underlines the importance of monocyte-macrophage cellular differentiation as a determinant of antibiotic penetration.
Antioxidant and Hepatoprotective Activity of Punicalagin and Punicalin on Carbon Tetrachloride-induced Liver Damage in Rats
Authors: Lin C C , Hsu Y F , Lin T C , Hsu F L , Hsu H Y 
Published: April 2011

Abstract
Punicalagin and punicalin, isolated from the leaves of Terminalia catappa L., are used to treat dermatitis and hepatitis. Both compounds have strong antioxidative activity. The anti-hepatotoxic activity of punicalagin and punicalin on carbon tetrachloride (CCl4)-induced toxicity in the rat liver was evaluated.
Levels of serum glutamate-oxalate-transaminase and glutamate-pyruvate-trans-aminase were increased by administration of CCl4 and reduced by drug treatment. Histological changes around the liver central vein and oxidation damage induced by CCl4 also benefited from drug treatment.
The results show that both punicalagin and punicalin have anti-hepatotoxic activity but that the larger dose of punicalin induced liver damage. Thus even if tannins have strong antioxidant activity at very small doses, treatment with a larger dose will induce cell damage.
Statins therapy: a review on conventional and novel formulation approaches
Authors: Tiwari Radheshyam , Pathak Kamla 
Published: April 2011

Abstract

Background and objective
High levels of cholesterol lead to atherosclerosis, a factor predisposing to the development of coronary artery disease. Statin drugs, i.e. HMG-CoA reductase inhibitors, have been known since the end of the last century for their benefits against cardio- and cerebrovascular diseases and are widely used clinically. This review aims at compiling the research inputs being made for developing therapeutically efficacious dosage forms that have the potential to surmount the limitations of conventional dosage forms of statins.

Key findings
Statin drugs can reduce the endogenous synthesis of cholesterol and prevent the onset and development of atherosclerosis, and are therefore used as an effective treatment against primary hypercholesterolemia. At present, statin drugs are most often administered orally, on a daily basis. After administration, the bioavailability and the general circulation of statin drugs is fairly low due to the first-pass metabolism in the liver and clearance by the digestive system. Extensive pharmaceutical research in understanding the causes of low oral bioavailability has led to the development of novel technologies to address these challenges.

Summary
These technologies vary from conventional dosage forms to nanoparticulate drug-delivery systems, and have the potential to cause improvements in bioavailability and consequently therapeutic efficacy.
EFFECTS OF PRACTICE AND REST ON FLUCTUATIONS IN THE MÜLLER–LYER ILLUSION
Authors: EYSENCK H. J. , SLATER P. 
Published: April 2011

Fifty subjects are given sixty trials each with an apparatus exhibiting the Müller–Lyer illusion. The first forty trials (divided for analysis into four periods of ten) are uninterrupted; a 30 sec. pause for fixation is followed by a fifth period of ten trials; and a rest pause of 30 min. by a final period. On the group as a whole, practice produces scarcely any effect. The means differ very little from trial to trial from period to period, and the amount of variation about them tends to remain constant. The effect of the illusion varies greatly on different individuals. The variance between the subjects' means for the experiment as a whole constitutes 63% of the total. There are also striking differences in the effects of practice on different subjects; these person:period interactions account for another 14%. The error variance forms almost the whole of the remainder (22%).To classify the person:period interactions, a principal component analysis was employed. The first latent root, accounting for 59% of the variance due to interaction, describes a course of change which retains the same direction for any particular subject (whether upwards or downwards, towards or away from the point of zero illusion) up to the end of the fifth period but is reversed by the rest pause. The authors do not consider the terminology of satiation or improvement with practice suitable for describing the whole range of such phenomena, but suggest a description in terms of habit reinforcement. However, the phenomena exhibited by subsequent components, which cannot be neglected as statistically non‐significant, do not seem so explicable. All such performances constitute patterns of search, and it is noteworthy that none of them accord with the oscillatory pattern suggested by cybernetic theory. Scores on scales of neuroticism and extraversion‐introversion failed to correlate significantly with individual differences either in the effect of the illusion over the experiment as a whole or in the progressive changes induced by practice.
THE EFFECTS OF DARKNESS AND LIGHT ON AUDITORY SENSITIVITY
Authors: ÖZBAYDAR SABRI 
Published: April 2011

This paper describes a group of experiments on the supposed effects of darkness and light on auditory sensitivity. The absolute threshold, differential threshold and masked threshold for a 1200 cyc./sec. tone, were measured in a total of forty‐six subjects, both when adapted to darkness, and to an ambient light of 25 ft.‐candles.There was a small, but reliable, improvement in both absolute and masked thresholds, in the light. No change was found in the differential threshold.Some introspective evidence was also obtained from twelve subjects.
READINESS TO PERCEIVE VIOLENCE AS A RESULT OF POLICE TRAINING
Authors: TOCH HANS H. , SCHULTE RICHARD 
Published: April 2011

A group of men who had undergone a three‐year course in law enforcement were tachistoscopically presented with a ‘violent’ picture to one eye, and a matched ‘neutral’ picture to the other. The results were compared with those obtained from novices in the training programme, and from psychology students.The trained subjects were found to see ‘violent’ scenes fully as often as they saw ‘neutral’ ones, whereas the control subjects reported comparatively few ‘violent’ pictures.It was concluded that specialized training may supplement past experience in areas in which the average person's experiences are inadequate. In this fashion, a person may become perceptually ‘sensitive’ in situations which ordinarily rarely occur.
CEREBRAL DOMINANCE IN REACTION TIME RESPONSES
Authors: KERR MYFANWY , MINGAY ROSEMARY , ELITHORN ALICK 
Published: April 2011

Previous experimental work has suggested that bilateral reaction times to visual stimuli may be subject to dominance effects, and that where pairs of stimuli are closely ordered in time, these effects may be more complex than a simple superiority in speed of performance by the dominant hand. Twenty subjects, ten markedly left handed and ten markedly right handed, were selected from a larger group of forty‐four subjects to examine these effects in detail.Results showed:

For single responses and paired responses to simultaneous stimuli, responses by the dominant hand were made significantly faster than by the non‐dominant hand.
A reversal of this effect occurred with the second responses to paired stimuli which were separated by an interval of 100 msec., the dominant responses being made significantly more slowly than the non‐dominant responses.
This reversal was a feature of the delayed responses only, i.e. of those responses where reaction time to the second stimulus was lengthened following a response to the first stimulus. Where the response to S2 was not delayed, dominance effects were in the same direction as for the single responses.
A subsidiary finding was that, apart from the relative magnitudes of response times, types of response to paired stimuli showed some relationship to individual dominance. In particular the response to S2 was more often delayed in the stimulus order non‐dominant/dominant than in the opposite order and responses were more often made independently in the order dominant/non‐dominant.
PROBABILITY LEARNING IN STEP‐INPUT TRACKING*
Authors: GIBBS C. B. 
Published: April 2011

Six men and six women tracked stimuli that demanded responses of unequal probability. The control‐display relation was directionally incompatible. Half the subjects used their non‐preferred hand. Many large directional errors occurred in early practice and these were amended after a mean delay of 0·24 sec. With continued practice, small errors persisted mainly in responses of low probability but the mean amendment time fell to 0·11 sec. These errors provided new, highly sensitive measures that revealed differences in performance associated with sex, hand preference and probability (P < 0·01).The results are compatible with hypotheses that the speed, direction and extent of movement are determined by negative proprioceptive feedback and integral‐error control (Gibbs, 1954).
PHENOMENAL SIMULTANEITY AND THE PERCEPTUAL MOMENT HYPOTHESIS
Authors: ALLPORT D. A. 
Published: April 2011

Successive brief visual stimuli falling within a critical time interval are phenomenally simultaneous. This paper examines two models of perceptual sampling which purport to account for phenomenal simultaneity. The first is Stroud's (1955) theory that the sensory input is quantized into successive, discrete summation periods or ‘moments’ (the Discrete Moment Hypothesis). An alternative model which has not generally been considered represents the ‘moment’ as a continuous, running sample of the input (the Travelling Moment Hypothesis).Two experiments on phenomenal simultaneity are reported which provide a critical test between these two hypotheses. The results were entirely incompatible with the discrete moment model, which is therefore rejected. The travelling moment model accounted well for the results. These also suggest a possible relation between the limits of phenomenal simultaneity and the critical duration of brightness summation.
REPRODUCTION OF KOHS‐TYPE FIGURES BY GHANAIAN CHILDREN: ORIENTATION ERRORS REVISITED
Authors: JAHODA GUSTAV 
Published: April 2011

First, a relationship was postulated between the experienced difficulty of patterns and the amount of disorientation of their reproductions. Secondly, while the major determinants of gross orientation errors among Africans seem to have been established, this in itself fails to explain why Europeans are little affected by them. It was proposed that the underlying factor might be the development of the concept of horizontality, which reduces dependence on the perceptual pull of the prevailing spatial framework.These notions were tested with 44 Ghanaian schoolboys aged between 10 and 16. The first relationship was clearly confirmed. As for the second, there was some association between horizontality and rotation errors, but it failed to account for a major part of the variance. Ex post facto exploration of the data strongly suggests that degree of psychological differentiation is likely to be the key factor influencing rotation error.
THE EFFECT OF TASK COMPLEXITY AND SEQUENCE ON RULE LEARNING AND PROBLEM SOLVING
Authors: SWELLER J. 
Published: April 2011

Two experiments were carried out in order to test the effects of task sequence on the speed of rule learning and problem solving. Expt. I involved numerical rule‐learning tasks. One group of subjects was presented with the tasks using a simple‐complex sequence while another group was presented with the complex rather than the simple task initially. The simple‐complex order resulted in a far superior performance. Expt. II tested the effect of task difficulty and task precedence using problem‐solving tasks. Speed of problem solving was not found to be significantly affected by task order.These contrasting results were discussed in terms of hypothesis testing theory and learning hierarchies.
Inappropriate constancy scaling as a factor in the müller‐lyer illusion
Authors: MORRISON L. C. 
Published: April 2011

The inappropriate constancy theory of geometrical illusions assumes the existence of implicit depth cues which automatically set constancy scaling. In the present study the phenomenon of cue conflict has been employed to test for latent depth cues in the Müller‐Lyer figures.The technique consisted in introducing a stereoscopic disparity between the figures by means of an aniseikonic lens and measuring the perceived depth between the figures. The magnitude of the stereoscopic effect depends on whether the perspective cues augment or inhibit the stereoscopic depth cues. The results were inconsistent with the misapplied constancy theory, but confirmed Pike & Stacey's (1969) observation that the illusion of size may act as a depth cue.