bluuebunny/crossref_metadata_2025 huggingface dataset:
Degree of conversion in denture base materials for varied polymerization techniques 1
Authors: Bartoloni J. A. , Murchison D. F. , Wofford D. T. , Sarkar N. K.
Published: March 2003

New processing techniques for denture base acrylic resins have been introduced which have not comparatively quantified the residual monomer content. While proper processing keeps the residual monomer in a tolerable range for most patients, tissue irritation and reaction due to potentially higher residual monomer in these alternative techniques could be a clinical concern. Decreased degree of conversion may influence physical properties as well as biocompatibility. This investigation evaluated the residual monomer content of acrylic resins cured by three different polymerization modes. Materials (polymerization system) evaluated were: Lucitone 199® (conventional process), Accelar 20® (rapid boil‐out), and Acron MC® (microwave). Fourier transform infrared spectrometry (FTIR) was employed to determine the degree of conversion. All curing methods produced similar results (Lucitone 199®=92·7% (0·21), Acron MC®=92·6% (0·57), Accelar 20®=90·9% (0·73). Conversion for Accelar 20® (rapid boil‐out technique), though statistically different (P<0·05,
anova) from the other two materials and polymerization techniques, was only slightly less. It is unlikely that the rapid boil‐out technique would induce more adverse tissue responses than the other techniques included in this study.
Effects of plaque control on the patency and occlusion of dentine tubules in situ
Authors: Kawasaki A. , Ishikawa K. , Suge T. , Shimizu H. , Suzuki K. , Matsuo T. , Ebisu S.
Published: March 2003

To elucidate the nature of dentine hypersensitivity, the effects of plaque control on the patency and occlusion of dentinal tubules were investigated systematically in situ using human dentine slabs embedded in partial dentures. The dentine slabs were divided into three groups. In group I, the dentine slabs were kept in an oral cavity without plaque control. In group II, plaque was removed mechanically by brushing. Plaque control was carried out chemically using chlorhexidine in group III. After being kept in the oral cavities for 1, 2 and 3 weeks, the slabs were removed from the partial denture, followed by SEM observation to determine the morphological changes of the dentinal tubules. When no attempt was made to remove plaque, the diameter of tubule orifices increased to 390% of the original values within 3 weeks. In contrast, dentinal tubules were found to be occluded, i.e. the tubule orifices became <20% of the original value within 1 week when plaque control efforts were made, using either method of plaque control. We conclude that plaque control plays one of the key roles in the patency versus occlusion of dentinal tubules, and thus in the aetiology and natural reparative process of dentine hypersensitivity.
Curing depth of different shades of a photo‐activated prosthetic composite material
Authors: Tanoue N. , Koishi Y. , Matsumura H. , Atsuta M.
Published: March 2003

This study determined the depth of cure of different shades of a prosthetic composite material with the aim of evaluating the influence of shade variation on post‐curing material properties. Four light shades having small tabs (A1, B1, C1 and D2) and four dark shades having higher tabs (A4, B4, C4 and D4) of a prosthetic composite (Artglass) for body paste based on the Vita Lumin Shade guide were selected. Specimens of each shade were exposed with the proprietary photo‐curing unit (UniXS) for periods 20, 30, 60 and 90 s. The curing depth of the material for each shade was determined with a scraping technique described by the International Organization for Standardization (ISO 4049), and average values of groups of five specimens were compared using analysis of variance (ANOVA) and Scheffe’s S intervals (P < 0·05). The L*a*b* colour parameters of five specimens after 90 s exposure were measured using a small‐area dental colorimeter (ShadeEye) in order to determine the colorimetric differences. Three‐factor ANOVA revealed that the depth of cure was influenced by shade letter (A, B, C or D) and shade tab (1 and 2, or 4) as well as by the exposure period (P=0·05). Curing depth of the light shades was consistently greater than that of the dark shades. Among the eight shades selected, B1 shade demonstrated the greatest curing depth, while A4 shade exhibited the lowest curing depth. For all shades, longer exposure increased the depth of cure. All of the light shades exhibited higher L* values than any of the four dark shades. Curing depth of the composite material was found to be related to the Vita shade variation and the exposure period.
Histomorphometric analysis on bone dynamics in denture supporting tissue under masticatory pressure in rat
Authors: Ohara K. , Sato T. , Imai Y. , Hara T.
Published: March 2003

The bone dynamics under denture base has not been clarified sufficiently. The purpose of this study was to evaluate histomorphometrically the bone dynamics in denture supporting tissue with relation to the intensity of the masticatory pressure. The removable denture bases, which exerted four different regulated masticatory pressures (0·0, 1·0, 20·0 or 40·0 kPa), were inserted to the hard palate of the molar region of 22‐week‐old rats. The palatal tissues were excised from 1 to 12 weeks after denture insertion at intervals of 1 week and embedded in methyl‐methacrylate. No bone resorption was observed throughout the experimental period in the 0·0 and 1·0 kPa groups. In the 1·0 kPa group compared with the 0·0 kPa group, bone formation parameters except for bone formation rate significantly increased at 4 weeks, but there was no significant difference between these groups in the other experimental periods. In the 20·0 and 40·0 kPa groups, bone resorption was observed until 3 and 5 weeks, respectively, and the amounts of bone resorption (AoBR) were 45 ± 25 and 104 ± 21 μm, respectively. After bone resorption, bone formation parameters in these two groups showed transiently significant decrease compared with the 0·0 kPa group, but were the same time course as the 0·0 kPa group following this decrease. In conclusion, masticatory pressure caused different time courses of the bone dynamics in denture supporting tissue depending on the initial intensity of the pressure. The AoBR responded to the initial intensity of masticatory pressure. Bone formation following bone resorption did not cause equivalent recovery of the bone surface level to the level observed in the case without bone resorption in the present study.
Long‐term clinical evaluation of fracture and pulp injury following glass–ionomer cement or composite resin applied as a base filling in teeth restored with amalgam
Authors: De C. Luz M. A. A. , Ciaramicoli‐Rodrigues M. T. , Garone Netto N. , De Lima A. C. P.
Published: March 2003

The aim of this research was to analyse the long‐term clinical behaviour of two dental materials applied as filling under silver amalgam restorations: glass–ionomer cement (GIC) and composite resin with adhesive system (CR). In this study, 117 posterior teeth (29 premolars and 88 molars) were selected with carious lesions which resulted in great loss of dentin and cusps with unsupported enamel. After caries removal, cavities were prepared and totally filled with GIC or with CR. In a following visit, new cavities were prepared, leaving the employed filling material as a base and support for the enamel, which were then restored with silver amalgam. Restorations were evaluated periodically after 6 months and up to 5 years. Both fracture and pulpal involvement rates were low. Although differences could be observed in the behaviour of the materials, statistical survival estimation showed that the performances of GIC and CR as filling material were similar. There was a significant association both between kind of tooth (molar or premolar) and long‐term survival of the restorations; and between degree of unsupported enamel and the same long‐term survival. Our results confirmed that the technique in which GIC or CR are used as filling under silver amalgam restorations is clinically acceptable.
Occlusal support and head posture
Authors: Kibana Y. , Ishijima T. , Hirai T.
Published: March 2003

In order to examine the relationship between occlusal support and head posture, the electromyographic (EMG) activities of the jaw closing muscles and the sternocleidomastoid muscle during voluntary maximal clenching (VMC) under several conditions of occlusal support in eight healthy dentates were recorded and analysed. The head posture was also recorded simultaneously by the electromagnetic, 6‐degree‐of‐freedom tracking instrument (POLHMUS Co. 3 SPACE‐WIN*). In the VMC with lateral imbalance of occlusal support, EMG activity of the jaw closing muscles and the sternocleidomastoid muscle on the occlusal support side was greater than those on the non‐occlusal support side, and the neck was bent in the direction of the occlusal support side. Moreover, a positive correlation was found between the asymmetry of muscle activity (asymmetry index) of the sternocleidomastoid muscle and the angle of lateral bending of the neck. From these results, it can be said that lateral imbalance of the occlusal support could promote imbalance in sternocleidomastoid muscle activity, causing lateral bending of the neck. From this study, it is suggested that there is a close relationship between occlusal support and head posture.
A calculation of stress distribution in metal–porcelain crowns by using three‐dimensional finite element method
Authors: Aykul H. , Toparli M. , Dalkiz M.
Published: March 2003

The objective of this study was to calculate stress distribution in a maxillary second premolar tooth which occurred by the mastication force. The tooth model was crowned with Au–Pd alloy, Ni–Cr alloy and porcelain. A load of 450 N, at an angle of 45° to the longitudinal axis was applied on the occlusal margin of the crown tooth. The tooth was assumed isotropic, homogenous, elastic and unsymmetrical. This numerical study was carried out using three‐dimensional finite element models and calculation programs were prepared by the authors using FORTRAN 77. The distribution of compressive, tensile and shear stress were plotted for the dentine, dentine–metal and metal–porcelain interfaces. The highest stress values were observed when Ni–Cr alloy and porcelain was used.
The effect of ambient light on QLF analyses
Authors: Pretty I. A. , Edgar W. M. , Higham S. M.
Published: March 2003

The use of optical methods in the diagnosis of early caries is developing rapidly. The introduction of the quantitative light‐induced fluorescence (QLF) device has promised the use of a quantifiable technique in vivo. This study describes the effect that ambient light has upon the reliability of QLF analyses. Using human teeth and simulated lesions the study examined the effect of 15 different light levels on three severities of carious lesions. The study found that a light level of 88 lux could be employed in areas where QLF is to be used without significantly affecting the reported value, ΔQ. This study impacts upon the health and safety issues surrounding QLF usage as well as ethical issues relating to working in dark environments.
Oral mucosal versus cutaneous sensory testing: a review of the literature
Authors: Jacobs R. , Wu C.‐H. , Goossens K. , Van Loven K. , Van Hees J. , Van Steenberghe D.
Published: March 2003

summary The innervation of skin and oral mucosa plays a major physiological role in exteroception. It also has a clinical interest as illustrated by sensory changes after neurosurgical procedures. These sensory changes often rely only on the patients' subjective reports, although objective assessments are possible. This review compares the neurophysiological features of the trigeminal sensory pathways with those of cutaneous sensory innervation. In this review, three receptor groups will be discussed: mechanoreceptors, thermoreceptors and nociceptors. Differences between receptors in the glabrous skin, the hairy skin and the oral mucosa will be highlighted. Sensory testing devices have been developed to quantify psychophysiological parameters such as the threshold level for receptor activation upon mechanical stimulation, but such devices have been merely developed to determine the threshold of skin receptors (tactile, thermal). Later on, some have been adapted to suit the particularities of the oral environment. This review attempts to compare the available literature on test devices for oral versus cutaneous tactile function. It summarizes what is common or rather particular to the devices used to study either cutaneous or oral receptors.
Recurrent headache in patients with temporomandibular disorders of mainly arthrogenous origin. A short‐ and long‐term evaluation of the treatment effect of occlusal appliance therapy. A randomized controlled trial
Authors: NILNER M. , EKBERG E. , VALLON D.
Published: March 2003

Introduction:  In patient material recurrent headache has been presented in about 40–70%.

Aim:  The aim of this study was to evaluate recurrent headache before and after treatment with a stabilization or control appliance. The effect of treatment should be evaluated both in a short and long time perspective.

Materials and methods:  Sixty patients with TMD of mainly arthrogenous origin were selected from patients referred for treatment of TMD. The patients were randomly assigned to a treatment group (T), stabilization appliance, and a control group (C), control appliance. The study was performed as a randomized controlled trial evaluating the treatment effect after 10 weeks, 6 and 12 months. Patients who reported a negative treatment outcome and/or any discomfort associated with the appliances either had their appliances adjusted or received a stabilization appliance creating a new mixed group (M).

Results:  In the T and C groups, 77 and 83% respectively, reported headache at least once a week before treatment. At the 10 week follow‐up a statistically significant difference was found regarding less frequent headache within the T‐group but not within the C‐group. Frequent headache was also found statistically significantly less often in the T‐group compared with the C‐group. At the 6 and 12 month follow‐ups the frequency of headache seemed to have diminished within groups.

Conclusion:  Treatment with a stabilization appliance seems to have a positive effect on recurrent headache in a short‐ and long‐term perspective in patients with TMD of mainly arthrogenous origin.
Buccal and lingual activity during mastication and swallowing in typical adults
Authors: Casas M. J. , Kenny D. J. , Macmillan R. E.
Published: March 2003

summary  A non‐invasive protocol was developed to assess tongue and cheek movements during mastication and to evaluate the temporal relationship between mastication and the initiation of pharyngeal swallowing. Typical adults (three males and three females) were monitored during chewing. Miniature pressure transducers were bonded unilaterally to the buccal and lingual surfaces of the first mandibular molar and the buccal surface of the first maxillary molar on each subject's preferred chewing side. Surface electromyography of the ipsilateral masseter muscle was recorded as an indicator of jaw‐closing activity. Pressure and electromyography (EMG) recordings were time‐linked to simultaneous B‐mode ultrasound imaging of the oral cavity using a submental, coronal view aligned with the first mandibular molar. The intervals between peak pressure recorded at each pressure transducer and peak jaw‐closing activity for each masticatory cycle were not statistically different [analysis of variance (anova), P=0·9856] and displayed large statistical variation. These intervals were not different at the beginning of the trials (hard biscuit) than they were at the completion of mastication when the cookie had been broken down to a paste/puree consistency bolus. The interval between the last chewing stroke and the initiation of swallowing was 0·92 ± 0·34 s). No significant difference existed among subjects for this time interval (anova, P=0·382).
Evidence of an influence of asymmetrical occlusal interferences on the activity of the sternocleidomastoid muscle
Authors: Ferrario V. F. , Sforza C. , Dellavia C. , Tartaglia G. M.
Published: March 2003

summary  To investigate the hypothesis of a functional coupling between occlusion and neck muscles, the immediate effect of asymmetrical occlusal interferences on the pattern of contraction of the sternocleidomastoid muscles (SCM) during maximum voluntary clench (MVC) was analysed in 30 healthy subjects. All subjects had a complete and sound permanent dentition, without temporomandibular joint (TMJ) and craniocervical disorders. A 5‐s surface electromyogram (EMG) examination of the SCM was performed during (1) MVC in intercuspal position and (2) MVC with a single 200‐μm occlusal interference alternatively positioned on teeth 16, 13, 23, 26. All subjects had a symmetrical EMG activity during MVC in intercuspal position. For each subject, SCM potentials were standardized as percentage of the mean potentials recorded during the MVC on natural dentition and the EMG waves of left‐ and right‐side muscles were compared by computing the relevant percentage overlapping coefficient (POC). For each subject, the best and the worst POCs computed during the four MVC tests with occlusal interferences were found and the percentage difference between them was calculated. In the four MVC tests with occlusal interferences, SCM symmetry was very different from that recorded during MVC on natural dentition. The difference between the best and worst POCs computed within each subject was very variable, ranging from 1·52 to 41·57%. In conclusion, when young healthy subjects with a normal occlusion clench on an asymmetrical occlusal interference, they have an altered left‐right side pattern of contraction of their SCM. In almost all subjects, a previously symmetrical pattern became asymmetrical.
A new and simple method for evaluating masticatory function using newly developed artificial test food
Authors: Sato H. , Fueki K. , Sueda S. , Sato S. , Shiozaki T. , Kato M. , Ohyama T.
Published: March 2003

summary  The aim of this study was to develop an objective evaluation system for the masticatory function. This system used paraffin wax cubes as a test food, which had six red‐ and green‐coloured layers so that each of the six surfaces showed a pseudo‐checkered pattern. A total of 100 paraffin cubes were chewed by 37 subjects and the images of these samples were captured and analysed using a digital image analyzer. With regard to the colour and the shape of each sample, five parameters were obtained. Furthermore, an independent examiner graded the degree of colour mixing in the chewed samples into three groups (poor, medium and good) by visual inspection. A discriminant analysis was performed using the five variables as predictors of two groups (good and poor). Mixing Ability Index (MAI) was calculated from the discriminant function and using this index, 97% of the samples from these two groups were classified correctly. This system needed only a few minutes to complete and is easy to use. Therefore, it has high potentials for clinical use.
Condylar movement analysis in subjects with clinically normal temporomandibular joints, utilizing an amorphous sensor
Authors: Ioi H. , Counts A. L. , Nanda R. S.
Published: March 2003

summary  The purpose of this study was to determine the range of condylar movements in normal subjects, by the use of an amorphous sensor. The pair‐matched sample consisted of 17 Caucasian males (aged 25·8 ± 2·5 years) and 17 Caucasian females (aged 25·5 ± 2·8 years) who had no subjective or objective symptoms related to temporomandibular joint (TMJ) sounds. Bilateral condylar and jaw movements were recorded simultaneously. The results showed that the typical condylar movement points plotted on the X–Y coordinates indicated a uniform or approximately straight line, that is X = Y. The mean ± standard deviation (s.d.) for the maximum velocity of condylar movement during the opening and closing phases was 32·6 ± 16·9 and 39·8 ± 21·5 mm s−1, respectively. The mean ± s.d. for the degree of jaw opening at the turning point of condylar movement was 36·9 ± 21·7%. Significant correlations existed between any two measurements of maximum velocity of condylar movement. Moreover, significant correlations existed between the left and right sides in the degree of jaw opening at the turning point of condylar movement. These results suggest that a range of normal values of condylar movements can be developed when utilizing the amorphous sensor method.
Prevalence of auditory hallucinations in nurses in mental health
Authors: Millham  , Easton
Published: March 2003

Seventy‐nine nurses and student nurses working in the mental health field were asked to complete a questionnaire that asked about the prevalence of their experience of events that might be considered as examples of auditory hallucinations. Eighty‐four per cent of the 55 nurses who returned the questionnaire described having experiences that might be described as auditory hallucinations. This level of prevalence is broadly consistent with other studies, and the difference between voices considered to indicate ‘schizophrenia’ and voices perceived as normal or unimportant is discussed. The relevance of these findings for the process of diagnosis and for the attitudes of nurses working in the mental health field towards voices reported by clients is highlighted.
Creating alliances: the views of users and carers on the education and training needs of community mental health nurses
Authors: Simpson A.
Published: March 2003

The Sussex Education and Training Consortium commissioned a development project to identify the education and training needs of Community Mental Health Nurses (CMHNs) working with people with severe mental illness. The concerns of various stakeholding groups were identified using a qualitative methodology, Responsive Evaluation. This paper reports the views of 52 service users and representatives and 24 carers and carer support workers as expressed in semi‐structured interviews and focused discussion groups. Users and carers were able to identify specific areas that require attention in the education and training of CMHNs. Users want CMHNs to have wide knowledge of mental illness, medication, therapies and services and the understanding and confidence to work in an empowering way. They also want CMHNs to systematically involve users and their carers in care planning and to make more explicit any communication with other professionals and agencies. Carers want more involvement and information and CMHNs made more aware of the role that carers play and the specific problems they face. Users and their organisations would like significant involvement in the provision of CMHN education and training at all levels. Developments to CMHN education and training are suggested with recommendations for research and evaluation.
The development and testing of the Mental Health Problems Perception Questionnaire
Authors: Lauder W. , Reynolds W. , Reilly V. , Angus N.
Published: March 2003

This paper reports the development and psychometric testing of the Mental Health Problems Perception Questionnaire. This questionnaire was developed to measure the therapeutic commitment, role support and role competency of non‐mental health specialist nurses (generalists) to working with patients with mental health problems who live in rural communities. The instrument was demonstrated to be valid and reliable in this population. The questionnaire was underpinned by an explicit theoretical model which facilitates an understanding of the factors that influence effective psychosocial nursing interventions with this client group.
A conceptual model for clinical supervision in nursing and health visiting based upon Winnicott’s (1960) theory of the parent–infant relationship
Authors: Rafferty M. A.
Published: March 2003

This paper consists of a review of mostly nursing literature with the purpose of developing a conceptual framework for understanding the process of clinical supervision and the nature of the supervisory relationship utilizing a psychodynamic perspective. The paper explores the experiences of nurses and health visitors during clinical supervision in order to illustrate how the dynamics of clinical supervision can be understood and enriched by using the concepts ‘Holding, handling and object presenting’ (Winnicott 1960) as a conceptual schema.
The relationship between involvement in activities and quality of life for people with severe and enduring mental illness
Authors: Kelly S. , McKenna H. , Parahoo K. , Dusoir A.
Published: March 2003

A number of authors have indicated that people who have greater and more satisfactory social activity tend to report that they have higher life satisfaction. This study was concerned with examining the relationship between involvement in activities and self‐reported quality of life for people with severe and enduring mental illness. It is part of a larger study of quality of life for this client group. A random sample of 92 respondents was drawn from the population of people who met the criteria for severe and enduring mental illness in a Health Board in Northern Ireland. Data were gathered using a reliable and valid interview schedule based on a quality of life profile developed for the larger study. The findings indicated that over half of the respondents (56.5%, n = 52) had no structured activity in their everyday life and there was a low level of participation in 14 listed activities of living. The respondents also reported a low level of self‐reported quality of life. There was also a weak, but statistically significant, correlation between involvement in activities and self‐reported quality of life. However, a moderate positive statistically significant correlation was found to exist between satisfaction with involvement in activities and self‐reported quality of life. The implications for the care of people who are experiencing severe and enduring mental illness within and outside the United Kingdom are discussed.
Women in special hospitals: understanding the presenting behaviour of women diagnosed with borderline personality disorder
Authors: Wilkins T. M. , Warner S.
Published: March 2003

This paper critically examines the development of the concept of borderline personality disorder (BPD) in terms of the assumed centrality of abnormal early environments and abusive relationships. It is suggested that if BPD is conceptualized as an expression of past experiences in adult life, information regarding early histories can assist in ‘making sense’ of later behaviour. The aim of this review therefore is to explore how histories of women diagnosed as BPD, within a High Secure Psychiatric Hospital, may facilitate an interpretation of the ‘adaptive’ nature of presenting ‘symptomology’. Case note material is utilized to gain insight into specific aspects of childhood experiences that have been documented, and are thus deemed significant. These findings support the perception that the role of the early environment and associated relationships are significant within written accounts of women diagnosed as having BPD. By exploring the links between trauma and BPD, this article suggests that an understanding of the effects of trauma and the importance of relationships can offer a way forward for self‐reflection and future care.
The aetiology, presentation and treatment of personality disorders
Authors: Tredget J. E.
Published: March 2003

Personality disorders are a heterogeneous collection of conditions with common features, which may include an exaggerated self‐centred nature, little regard for the feelings of others, or the regular fabrication of stories to explain the behaviour of self or others. Whilst such features might be recognized as being present in many people at different times of their lives, it is the persisting nature and extremes of personality traits that distinguishes those who have personality disorders from those who do not. Apart from the problems that personality disorders bring on their own (such as dysfunctional relationships), when they coexist with mental disorders it makes the latter more difficult to treat. People with personality disorders are often depicted as being dangerous, yet only a few are and it is this minority group that attract public attention. Personality disorders are recognized as belonging to the group known as the serious mental illnesses, a group that mental health nurses are being encouraged to focus their attentions on, but it is accepted that there is a paucity of education and training in appropriate interventions for this group of people. This article provides an overview of the aetiology and presentation of personality disorders together with an examination of evidence‐based therapeutic interventions.
In harm's way: a postmodern narrative inquiry
Authors: McAllister M. M.
Published: March 2003

Deliberate self‐harm is a traumatic experience which has serious consequences at individual and social levels. Differing motivations for self‐harm and different modes of injury require that therapeutic responses vary. Yet, according to the literature and personal observation, nursing responses tend to be uniform and inflexible. Not only are such responses inadequate for effectively dealing with individuals who self‐harm, they also have unintended, hidden deleterious consequences for nurses and nursing. In this paper, a story about self‐harm is analysed using a postmodern perspective that helps to illuminate multiple dimensions to this complex issue. The approach enriches understanding, opening up possibilities to improve the quality of the nurse–patient relationship.
Prion protein: a role in sleep regulation?
Authors: Huber  , Deboer  , Tobler
Published: March 2003

The prion protein (PrP) is a glycoprotein anchored to cell membranes and expressed in most cell types. Its structural features indicate possible relations to signal peptidases ( Glockshuber et al. 1998
). Since mutations in this protein lead to severe neurodegeneration and death in humans and animals, it is possible that the loss of its normal function contributes to the development of the pathology. Little is known about its normal function, but there are indications that it may play a role in circadian rhythm and sleep regulation in mice. We explored further whether PrP plays a role in sleep regulation by comparing sleep and the effects of 6 h sleep deprivation in PrP knockout mice and isogenic wild‐type mice of the 129/Ola strain. The mice did not differ in the amount and distribution of the vigilance states or in the power spectra. The most remarkable difference was the larger and long‐lasting increase of slow‐wave activity (mean EEG power density 0.75–4.0 Hz) in non‐rapid‐eye‐movement (NREM) sleep during recovery from sleep deprivation in the null mice. The results confirm our previous findings in mice with a mixed background. This observation applies also to slow‐wave activity in NREM sleep episodes following spontaneous waking bouts of different duration. Sleep fragmentation in both genotypes was larger than in mice with the mixed background. A new aspect was revealed by the spectral analysis of the EEG, where the null mice had a lower peak frequency within the theta band in REM sleep and waking, and not in NREM sleep. Behavioural observations concomitant with the EEG indicated that the EEG difference in waking may be attributed to the smaller amount of exploratory behaviour in the null mice. The difference between the genotypes in theta peak frequency was not an overall effect on the EEG, since it was absent in NREM sleep. PrP therefore may be affecting the theta‐generating mechanisms in the hippocampus during waking and REM sleep. It remains unresolved whether PrP plays a role in sleep consolidation, nevertheless the data suggest that it is involved in sleep regulation. A passive avoidance test showed a difference between the genotypes. It is not probable that this was due to memory differences, since the genotypes reacted similarly in a delayed T‐maze alternation procedure. The behavioural differences need to be pursued further.
Comparative pharmacokinetics of sulfamethazine in plasma and parotid saliva of sheep
Authors: Pulido E. , Meot F. , Sumano H. , Boivin R.
Published: March 2003

Salivary output in sheep is large enough to be considered a physiologic body fluid compartment. The hypothesis for this work was that pharmacokinetics of sulfamethazine in saliva was similar to that in plasma. A reliable technique was developed to measure parotid salivary output. Mean output of saliva was 3.18 ± 1.04 L from a single parotid gland per day with a mean flow of 2.21 ± 0.43 mL/min. Using concentrations of sulfamethazine in parotid saliva made it possible to calculate the total passage of sulfamethazine to parotid saliva, which was calculated to be 3.5% of the total dose. Pharmacokinetic variables obtained for sulfamethazine in plasma and in saliva were closely related (AUC1408 μg.h/mL andAUC1484 μg.h/mL;Vdarea0.434 L/kg andVdarea0.374 L/kg;t½β4.30 h and 3.46 h, respectively) and no substantial differences were observed. The convenience of using salivary concentrations of sulfamethazine for drug monitoring is discussed.
Pharmacokinetics of cisapride in the horse
Authors: Steel  , Bolton  , Preechagoon  , Charles
Published: March 2003

The purpose of this study was to determine the pharmacokinetics and absolute bioavailability of cisapride after intravenous (i.v.) and intragastric (i.g.) administration in healthy, adult horses. Five animals received single doses of 0.1 mg/kg, 0.2 mg/kg and 0.4 mg/kg cisapride by the i.g. route in an open, randomized fashion on different occasions separated by a washout period of at least 48 h. Four of these horses were also given a single i.v. dose of 0.1 mg/kg cisapride. Jugular venous blood was collected periodically up to 24 h after dosing. Plasma cisapride concentrations were measured by high‐performance liquid chromatography.

 There was considerable inter individual variability in pharmacokinetic parameters. The mean (SD) values for systemic clearance (Cl) and steady‐state volume of distribution (Vss) were 494 (43.6) mL/h/kg and 1471 (578) mL/kg, respectively. Although the rate of cisapride absorption was quite rapid, only about half the i.g. dose was absorbed systemically. The average terminal half‐life (t½) calculated over three i.g. doses was 2.06 h and that for i.v. administration was 2.12 h. The pharmacokinetics of cisapride from 0.1 mg/kg to 0.4 mg/kg were independent of the i.g. dose.
A toxicity study of eltenac, a nonsteroidal anti‐inflammatory drug, in horses
Authors: GOODRICH  , FURR  , ROBERTSON  , WARNICK
Published: March 2003

A double‐blind study was performed, in horses, to determine the potential toxic effects of the nonsteroidal anti‐inflammatory drug, eltenac(4‐[(2,6‐dichlorophenyl) amino]‐3‐thiopheneacetic acid). Four treatment groups of six horses were formed. The drug was injected intravenously, once daily, at a dose level of 0.5 mg/kg, 1.5 mg/kg or 2.5 mg/kg for 15 days. A control group was injected with sterile saline solution. Horses were monitored for changes in appetite, physical examinations, biochemical evaluations and gastroscopic examinations. Complete post‐mortem examinations were also performed. A few glandular gastric ulcers, mild in severity, developed in seven animals during the treatment period. This occurred more often in horses treated with high doses of eltenac (P= 0.02). A dose‐dependent change of white blood cell (WBC) count and neutrophil count was noted. Total protein, albumin and globulin levels had dose‐dependent decreases. One horse in the high dose group (2.5 mg/kg) developed ventral ooedema as well as hypoproteinaemia. Gross post‐mortem and histological examination did not reveal any signs of drug related gastrointestinal, renal or hepatic abnormalities. Toxic effects of eltenac given intravenously were greatest in horses treated with 2.5 mg/kg of the compound for 15 days compared to other groups.
Pharmacokinetics and metabolism of ketoprofen after intravenous and intramuscular administration in camels
Authors: Alkatheeri  , Wasfi  , Lambert
Published: March 2003

The pharmacokinetics of ketoprofen were determined after an intravenous (i.v.) and intramuscular (i.m.) dose of 2.0 mg/kg body weight in five camels (Camelus dromedarius) using gas chromatography/mass spectrometry (GC/MS). The data obtained (median and range) following i.v. administration was as follows: the elimination half‐life (t½β) was 4.16 (2.65–4.29) h, the steady state volume of distribution (Vss) was 130.2 (103.4–165.3) mL/kg, volume of distribution (area method) (Vdarea) was 321.5 (211.4–371.0) mL/kg, total body clearance (Cl) was 1.00 (0.88–1.08) mL/min.kg and renal clearance was 0.01 (0.003–0.033) mL/min.kg. Following i.m. administration, the drug was rapidly absorbed with peak serum concentration of 12.2 (4.80–14.4) μg/mL at 1.50 (1.00–2.00) h. The systemic availability of ketoprofen was complete. The apparent half‐life was 3.28 (2.56–4.14) h. A hydroxylated metabolite of ketoprofen was identified by (GC/MS) under electron impact (EI) and chemical ionization (CI) scan modes. The detection times for ketoprofen and hydroxy ketoprofen in urine after an intravenous (i.v.) dose of 3.0 mg/kg body weight was 24.00 and 70.00 h, respectively. Serum protein binding of ketoprofen at 20 μg/mL was extensive; (99.1 ± 0.15%).
The disposition of theophylline in camels after intravenous administration
Authors: Wasfi  , Elghazali  , Boni  , Hadi  , Alhadrami  , Almuhrami  , Alkatheeri  , Barezaiq  , Agha  , Wajid
Published: March 2003

The pharmacokinetics of theophylline were determined after an intravenous (i.v.) dose of 2.36 mg/kg in six camels and 4.72 mg/kg body weight in three camels. The data obtained (median and range) for the low and high dose, respectively, were as follows: the distribution half‐lives (t1/2α) were 1.37 (0.64–3.25) and 2.66 (0.83–3.5) h, the elimination half‐lives (t1/2β) were 11.8 (8.25–14.9) and 10.4 (10.0–13.5) h, the steady state volumes of distribution (Vss) were 0.88 (0.62–1.54) and 0.76 (0.63–0.76) L/kg, volumes of the central compartment (Vc) were 0.41 (0.35–0.63) and 0.51 (0.36–0.52) L/kg, total body clearances (Clt) were 62.3 (39.4–97.0) and 50.2 (47.7–67.4) mL/h.kg body weight and renal clearance (Vr) for the low dose was 0.6 (0.42–0.96) mL/h.kg body weight. There was no significant difference in the pharmacokinetic parameters between the two doses. Theophylline protein binding at a concentration of 5 μg/mL was 32.2 ± 3.3%. Caffeine was identified as a theophylline metabolite but its concentration in serum and urine was small. Based on the pharmacokinetic values obtained in this study, a dosage of 7.5 mg/kg body weight administered by i.v. injection at 12 h intervals can be recommended. This dosing regimen should achieve an average steady state serum concentration of 10 μg/mL with peak serum concentration not exceeding 15 μg/mL.
Pharmacokinetics of clindamycin HCl administered intravenously, intramuscularly and subcutaneously to dogs
Authors: Lavy  , Ziv  , Shem‐Tov  , Glickman  , Dey
Published: March 2003

A buffered aqueous solution of clindamycin Hcl (200 mg/mL) was injected intravenously (i.v.) intramuscularly (i.m.) and subcutaneously (s.c.) in a non‐randomized, partial cross‐over trial involving six male and six female dogs. Blood samples were collected at conventional, predetermined time periods and serum drug concentrations were determined by microbiological assay. Dogs were observed clinically for signs of pain, and activity of serum creatine phosphokinase (CPK) was monitored after i.m. dosing.

The i.v. data from five of the dogs best fitted a two‐compartment open‐system pharmacokinetic model whereas a non‐compartment model was most suitable for analysis of the data from the remaining seven dogs. The mean i.v. elimination half‐life (t½β) and the mean residence time (MRT) were 124 and 143 min, respectively. The mean volume of distribution at steady state (Vss) was 0.86 L/kg. Little pain was recorded upon i.m. injection; mean peak serum drug concentration (Cmax) was 4.4 μg/mL, the elimination half‐life (t½el) was 247 min and the calculated bioavailability (F) was 115% of the i.v dose. Serum CPK activity was elevated to 25‐fold the pretreatment level in samples collected 4, 8 and 12 h after i.m. injection. Pain was not recorded after s.c. drug administration; the meanCmaxof 20.8 μg/mL was significantly greater than the corresponding value for the i.m. route, andFwas 310%. The s.c. route appears to be superior to the i.m. route in terms of local tolerance and serum drug level; a 10 mg/kg SID treatment regimen is suggested for treatment of canine infections due to clindamycin sensitive bacteria.
The oral bioavailability of ibuprofen enantiomers in broiler chickens
Authors: Vermeulen B. , Remon J. P.
Published: March 2003

Doses of racemic ibuprofen ranging from 5 to 20 mg/kg body weight were administered intravenously (i.v.) and orally to broiler chickens and plasma concentration–time profiles for both ibuprofen enantiomers were determined. The absorption of ibuprofen was evaluated after a bolus administration of a commercially available suspension into the crop and proventriculus, respectively. An enterohepatic circulation as described for other nonsteroidal anti‐inflammatory drugs (NSAIDs) in other species could be suggested for both enantiomers after i.v. and oral administration. Significantly higher area under the curve (AUC) values for S(+)‐ibuprofen compared with R(−)‐ibuprofen were collected after crop and proventriculus administration. Several factors could be responsible for the significant differences inAUCvalues between both enantiomers.
Differential inhibition of equine neutrophil function by phosphodiesterase inhibitors
Authors: Rickards K. J. , Page C. P. , Lees P. , Cunningham F. M.
Published: March 2003

Rickards, K. J., Page, C. P., Lees, P., Cunningham, F. M. Differential inhibition of equine neutrophil function by phosphodiesterase inhibitorsJ. vet. Pharmacol. Therap.24,275–281.

Neutrophils are recruited to the lungs of horses with chronic obstructive pulmonary disease (COPD) and exhibit increased activity after antigen challenge, which may contribute to inflammation and lung damage. Inhibition of phosphodiesterase isoenzymes (PDEs) has been shown to attenuate human neutrophil functions including superoxide production, leukotriene (LT)B4biosynthesis, enzyme and chemokine release. As equine neutrophils contain predominantly the isoenzyme, PDE4, the present study was undertaken to investigate the effects of rolipram, a PDE4 inhibitor, on equine neutrophil function. For comparison, the effects of the nonselective PDE inhibitor, theophylline, were examined. Cells from both normal horses and COPD horses in remission were used. Superoxide production was significantly inhibited by both rolipram [32.2 ± 2.6 vs. 10.1 ± 1.1 nmol/106cells and 49.8 ± 6.8 vs. 22.7 ± 2.2 nmol/106cells for normal and COPD susceptible horses, respectively, in response to 10–7 Mhuman recombinant (hr) C5a] and theophylline (19.0 ± 0.6 vs. 10.2 ± 0.6 nmol/106cells and 24.3 ± 2.1 vs. 10.7 ± 0.9 nmol/106cells for normal and COPD susceptible horses, respectively, in response to 10–7 MC5a). However, superoxide production induced by serum treated zymosan was inhibited only by theophylline (10–3 M). Neither hrC5a‐ nor platelet activating factor (PAF)‐induced neutrophil adherence to fibronectin coated plastic was reduced by rolipram (10–5 M). These results demonstrate that the effects of PDE inhibitors on equine neutrophils are both stimulus and function dependent. The PDE4 inhibitors may reduce neutrophil activationin vivoin horses with COPD.
Residue depletion of thiamphenicol in the sea‐bass
Authors: INTORRE L. , CASTELLS G. , CRISTÒFOL C. , BERTINI S. , SOLDANI G. , ARBOIX M.
Published: March 2003

The residue depletion of thiamphenicol (TAP) was investigated in the sea‐bass (Dicentrarchus labrax) after 5 days' treatment with medicated food at a dose of 15 or 30 mg/kg bw/day. Fish were sampled for blood and muscle + skin from 3 h until 14 days after treatment. Thiamphenicol concentrations were assayed by high performance liquid chromatography. Thiamphenicol concentrations measured 3 h after stopping treatment were 0.77 μg/mL and 0.91 (15 mg/kg dose) or 1.32 μg/mL and 1.47 μg/g (30 mg/kg dose), in plasma and muscle + skin, respectively. After a withdrawal of 3 days, plasma and tissue concentrations were: 0.08 μg/mL and 0.03 μg/g (lower dose) or 0.12 μg/mL and 0.06 μg/g (higher dose), respectively. Thiamphenicol was not detectable either in plasma or in tissues on days 7, 10 and 14 following withdrawal of the medicated food. Based on maximum residue levels (MRL) for TAP in fin fish, established at 50 μg/kg for muscle and skin in natural proportions, a withdrawal period of 5 and 6 days is proposed, after treatment at 15 or 30 mg/kg of TAP with medicated feed pellets, respectively, to avoid the presence of violative residues in the edible tissues of the sea‐bass.
Enzyme and plasma protein induction by multiple oral administrations of phenobarbital at a therapeutic dosage regimen in dogs
Authors: HOJO T. , OHNO R. , SHIMODA M. , KOKUE E.
Published: March 2003

In dogs effects of phenobarbital (PB) on hepatic cytochrome P450 (CYP) activities and on concentrations of plasma α1‐acid glycoprotein (AGP) were examined. Total body clearance (ClB) of antipyrine and plasma AGP concentrations were monitored during oral PB treatment at a therapeutic dose for 35 days. ClB of antipyrine, which reflects hepatic CYP activities, gradually increased and was maintained at about threefold concentrations compared with that before treatment, suggesting that PB induced CYP activities at a large extent even in a therapeutic dose, necessary for an antiepileptic effect. Plasma AGP concentrations also increased significantly (about fourfold). Dogs were killed at the 35th day of the PB treatment, and hepatic CYP content and enzyme kinetics of several CYPs were determined using liver microsomes. CYP content was about twofold higher than that from untreated dogs. The Vmax values for CYP1A‐like activity (ethoxyresorufin O‐deethylation), 2B‐like activity (ethoxycoumarin O‐deethylation), 2C‐like activity (tolbutamide hydroxylation) and 3A‐like activity (midazolam 4‐hydroxylation) were higher (2–4‐fold) than that in untreated dogs. In summary, a therapeutic dose of PB for antiepileptic therapy significantly induced hepatic CYPs and plasma AGP in dogs. Therefore, during antiepileptic therapy with PB, special attention must be paid to the pharmacokinetics of drugs simultaneously administered.