bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vivo Gene Transfer Studies on the Regulation and Function of the Vasopressin and Oxytocin Genes
Authors: Murphy D. , Wells S. 
Published: March 2003

AbstractNovel genes can be introduced into the germline of rats and mice by microinjecting fertilized one‐cell eggs with fragments of cloned DNA. A gene sequence can thus be studied within the physiological integrity of the resulting transgenic animals, without any prior knowledge of its regulation and function. These technologies have been used to elucidate the mechanisms by which the expression of the two genes in the locus that codes for the neuropeptides vasopressin and oxytocin is confined to, and regulated physiologically within, specific groups of neurones in the hypothalamus. A number of groups have described transgenes, derived from racine, murine and bovine sources, in both rat and mouse hosts, that mimic the appropriate expression of the endogenous vasopressin and genes in magnocellular neurones (MCNs) of the supraoptic and paraventricular nuclei. However, despite considerable effort, a full description of the cis‐acting sequences mediating the regulation of the vasopressin‐oxytocin locus remains elusive. Two general conclusions have nonetheless been reached. First, that the proximal promoters of both genes are unable to confer any cell‐specific regulatory controls. Second, that sequences downstream of the promoter, within the structural gene and/or the intergenic region that separates the two genes, are crucial for appropriate expression. Despite these limitations, sufficient knowledge has been garnered to specifically direct the expression of reporter genes to vasopressin and oxytocin MCNs. Further, it has been shown that reporter proteins can be directed to the regulated secretory pathway, from where they are subject to appropriate physiological release. The use of MCN expression vectors will thus enable the study of the physiology of these neurones through the targeted expression of biologically active molecules. However, the germline transgenic approach has a number of limitations involving the interpretation of phenotypes, as well as the large cost, labour and time demands. High‐throughput somatic gene transfer techniques, principally involving the stereotaxic injection of hypothalamic neuronal groups with replication‐deficient adenoviral vectors, are now being developed that obviate these difficulties, and which enable the robust, long‐lasting expression of biologically active proteins in vasopressin and oxytocin MCNs.
Termination of Neuroendocrine Refractoriness to Melatonin in Siberian Hamsters (Phodopus sungorus)
Authors: Kauffman A. S. , Freeman D. A. , Zucker I. 
Published: March 2003

AbstractSiberian hamsters maintained from birth in a short day length (DL), unlike their long‐day counterparts, fail to undergo reproductive development by 5 weeks of age. Instead, reproductive maturation of short‐day males is delayed for approximately 20 weeks, at which point neuroendocrine refractoriness to the inhibitory effects of short DLs develops, resulting in growth of the gonads. To terminate refractoriness and re‐establish responsiveness to short photoperiods, 10–15 weeks of long‐day exposure is required. We assessed whether continuous exposure to long days is necessary to terminate refractoriness or whether the first few weeks of long days initiate a process that culminates several months later in the breaking of refractoriness. Male hamsters refractory to short DLs were transferred to a long‐day photoperiod, pinealectomized (PINx) after 0, 3, 6 or 15 weeks, and subsequently infused for 6 weeks with a short‐day melatonin signal. This melatonin treatment induces gonadal regression in photosensitive but not in photorefractory hamsters. Six percent of males PINx at week 0 and 88% of those PINx at week 15 underwent gonadal atrophy by the end of the melatonin infusion treatment initiated on week 15. Among hamsters PINx on week 6, 17% versus 76% underwent testicular involution in response to melatonin infusions initiated on week 6 and week 15, respectively. This finding indicates that a fraction of the long days that hamsters experience during spring and summer are sufficient to trigger the processes that restore responsiveness to short DLs. Additional groups of pineal‐intact photorefractory animals were given 3, 6 or 15 weeks of long‐day exposure and then returned to a short DL for several months; only those treated for 15 weeks terminated refractoriness. The breaking of refractoriness, once triggered by long‐day melatonin signals, proceeds to completion only in the absence of short‐day melatonin signals.
A retrospective study of combined fixed–removable reconstructions with their analysis of failures
Authors: Studer S. P. , Mäder C. , Stahel W. , Schärer P. , O Department , Fixed F , Prosthodontics Removable , Materials Dental , O School , Medicine F Dental , University Zürich , Statistics And , O Swiss Federal Institute , F Technology  , Eth  , Zürich  , Switzerland  
Published: March 2003

SUMMARYThe survival rate and the reasons for failures of 130 combined fixed–removable reconstructions (CFR), incorporated in 112 patients, were assessed. Each CFR reconstruction was classified depending on its attachments: 76 reconstructions were attached with rigid, precise attachments, and constituted the rigid group; 54 reconstructions were attached with either semi‐precision or individual attachments and were defined as the semi‐rigid group. Of the 130 reconstructions, 41 were determined as complete successes, 39 as partial successes and 50 as failures, leading to 37 major repairs and to 13 new reconstructions. Three reconstructions failed due to technical reasons, 36 due to biological reasons and for 11 reconstructions, both categories of reasons were responsible for their failure. In total, technical reasons were counted 15 times in comparison to 73 biological reasons for those 50 failed reconstruction, with 29 fractured abutment teeth as the most common biological reason. Within the rigid group, 45 failed reconstructions were observed, whereas within the semi rigid group only 5 failures occurred, leading to an 8‐year survival estimate (± SD) of 30·1% (± 6·9%) for the rigid group and 93·1% (± 3·9%) for the semi rigid group. Beside the attachment type, the anatomy of the partially edentulous tooth arch in form of the free‐end situation and the dentate opposing jaw were identified as risk factors.
Maximum bite force after the replacement of complete dentures
Authors: MÜLLER F. , HEATH M. R. , OTT R. 
Published: March 2003

In complete denture wearers the maximum bite force (MBF) is known to be considerably lower than in dentate people. Low MBF might therefore be an indication of poor denture fit but there is limited evidence on this. Therefore, the aim of the present study was to investigate whether MBF can be improved by the replacement of complete dentures for elderly people.Nine edentulous volunteers, average age 74·2 ± 5·5 years and average denture experience 19·4 ± 19·5 years (1–50 years), had replacement dentures made. Functional impressions were taken after border moulding using zinc oxide eugenol paste. After a rehearsal session, MBF was recorded with the old dentures, and with the new dentures immediately at insertion, at 3, 8 days, 2–3 weeks, 1, 2, 3 and 6–10 months post‐insertion (p.i.). The MBF was recorded with the central bearing point method using a full‐bridge strain gauge with a confirmed linearity from 1 to 1000 N and an accuracy of ±1 N. Data were analysed off‐line using the mean of two peak readings per patient per session.The results indicate that MBF tended to be impaired when replacement dentures were first fitted (n.s.). However, this trend reversed during the first month p.i. for patients with a ‘moderate’ lower ridge resorption of Atwood (1963) grade 3 or 4 (n=5). Patients with more severe lower ridge resorption (Atwood grade 5 or 6; n=4) showed a significantly lower MBF over the entire observation period (P=0·05) and took longer to regain bite strength. Only patients with moderate bone resorption exceeded their pre‐insertion level of MBF within the observation period of 6–10 months p.i. In contrast to one report of immediate improvement of MBF at insertion of a new or relined denture (Leyka et al., 2000), the present study suggests that, at least for elderly patients with severe bone resorption, delayed improvement of MBF should be expected.
Bright light treatment used for adaptation to night work and re‐adaptation back to day life. A field study at an oil platform in the North Sea
Authors: Bjorvatn BjØRn , Kecklund GÖRan , Åkerstedt TorbjÖRn 
Published: March 2003

SummaryNight workers complain of sleepiness, reduced performance and disturbed sleep due to lack of adjustment of the circadian rhythm. In simulated night‐work experiments scheduled exposure to bright light has been shown to reduce these complaints. Here we studied the effects of bright light treatment on the adaptation to 14 days of consecutive night work at an oil platform in the North Sea, and the subsequent re‐adaptation to day life at home, using the Karolinska sleep/wake diary. Bright light treatment of 30 min per exposure was applied during the first 4 nights of the night‐shift period and the first 4 days at home following the shift period. The bright light exposure was scheduled individually to phase delay the circadian rhythm. Bright light treatment modestly facilitated the subjective adaptation to night work, but the positive effect of bright light was especially pronounced during the re‐adaptation back to day life following the return home. Sleepiness was reduced and the quality of day was rated better after exposure to bright light. The modest effect of bright light at the platform was, possibly, related to the finding that the workers seemed to adapt to night work within a few days even without bright light. These results suggest that short‐term bright light treatment may help the adaptation to an extended night‐work period, and especially the subsequent re‐adaptation to day life.
Morningness/eveningness and the need for sleep
Authors: Taillard Jacques , Philip Pierre , Bioulac Bernard 
Published: March 2003

SummaryThe purpose of this study was to determine, in a large sample of adults of all ages (17–80 years), the effect of morningness/eveningness on sleep/wake schedules, sleep needs, sleep hygiene and subjective daytime somnolence. A total of 617 subjects (219 subjects per chronotype group) matched for age, sex and employment status, completed an abridged morningness/eveningness questionnaire, a questionnaire on sleep habits and the quality of sleep, and the Epworth Sleepiness Scale. Eveningness was associated with a greater need for sleep, less time in bed during the week compared to ideal sleep needs, more time in bed at the weekend, a later bedtime and waking‐up time especially at the weekend, more irregular sleep/wake habits and greater caffeine consumption. These subjects built up a sleep debt during the week and extended their duration of sleep at the weekend. They did not, however, rate themselves more sleepy than other types, despite the fact that our results showed a clear link between subjectively evaluated daytime somnolence and sleep debt. Why they were less affected by sleep deprivation is not clear. This raises the question of individual susceptibility to the modification of sleep parameters.
The effects of levetiracetam on objective and subjective sleep parameters in healthy volunteers and patients with partial epilepsy
Authors: Bell Caroline , Vanderlinden Hilde , Hiersemenzel Reinhard , Otoul Christian , Nutt David , Wilson Sue 
Published: March 2003

SummaryLevetiracetam is a novel antiepileptic drug which has recently been released as an adjunctive treatment for partial epilepsy. In the two studies reported here we examined the objective and subjective effects of levetiracetam on sleep in 12 healthy volunteers and 17 patients [16 who could be evaluated for electroencephalogram (EEG) recordings] with a history of partial epilepsy on stable carbamazepine monotherapy. The studies were of a similar double‐blind crossover placebo‐controlled design with subjects' sleep being recorded in their own homes. The results from the two studies showed considerable similarities. In both, levetiracetam produced an increase in the time spent in stage 2 sleep, which in the patient study was accompanied by a decrease in the time spent in stage 4 sleep and in the volunteer study an increase in rapid eye movement (REM) latency. The subjective changes included reports that sleep was of a better quality with fewer awakenings and patients also reported that their sleep was more restful. Volunteers and patients did, however, feel less alert on waking in the morning. Therefore, both groups reported a decrease in awakenings after levetiracetam despite the finding from the EEG of no change in the actual number of awakenings. It may be concluded from both studies that levetiracetam does affect some indicators of subjective sleep perception, but does not influence objective sleep measures of sleep continuity. The results from the patient study during placebo add‐on treatment also showed that patients on carbamazepine had a marked increase in SWS, an increase in stage 2 sleep and an increase in REM latency compared with healthy volunteers. Interestingly, levetiracetam also reduced bilateral epileptiform EEG activity, particularly in patients with more discharges.
Copulatory activity increases slow‐wave sleep in the male rat
Authors: Vazquez‐Palacios G. , Bonilla‐Jaime H. , Retana‐Marquez S. , Velazquez‐Moctezuma J. 
Published: March 2003

SummaryIt is believed that sexual activity increases the need to sleep in many species. However, the relationship between copulatory activity and sleep has been poorly studied. Several studies have observed variations in the sleep of female rats and women as a function of their reproductive state. These effects have been correlated with the effects of female steroid hormones, but not with sexual activity. The aim of the present study was to evaluate the sleep–wake pattern of male rats immediately after different conditions of copulatory activity. Sexually experienced male rats were chronically implanted with a standard set of electrodes for sleep recording. After a control sleep recording of 8 h, the males were randomly assigned to one of the following experimental conditions: 30 min in the presence of an ovariectomized (OVX) rat; 30 min in the presence of an intact non‐receptive female (NRF); with a receptive female until reaching one ejaculation (1E); and with a receptive female until reaching three ejaculations (3E). In addition, after 10 days, males were randomly exposed to one of the following copulatory conditions during 4 h: to remain in the presence of an OVX rat; to remain in the presence of an NRF female, and with receptive females until reaching sexual satiety (SS). Male sexual behavior was assessed just after the onset of the dark period, and sleep recordings were obtained during 8 h immediately after experimental testing. Both the three ejaculations group (3E) in the first experiment and the sexual satiety group (SS) in the second experiment showed enhanced percentages of time spent in slow wave sleep (SWS) II and a shorter latency to the first SWS II episode than in the control group or under basal conditions. In addition, neither the presence of a non‐receptive female or an OVX female, nor sexual behavior until reaching one ejaculation induced any effect on the sleep stages. These findings suggest that the increase in SWS II induced by both 3E and SS may be governed by some specific mechanism that is essentially independent of physical exercise or stress. Copulatory activity might be the source of neurohormonal processes that induce sleep and may involve the participation of gamma‐aminobutyric acid, serotonin or other endogenous regulators of sleep and wakefulness. Nevertheless, the precise mechanism by which the sexual behavior increases SWS is still to be determined.
Enantiospecific pharmacokinetics and pharmacodynamics of ketoprofen in sheep
Authors: Landoni  , Comas  , Mucci  , Anglarilli  , Bidal  , Lees  
Published: March 2003

Pharmacokinetic and pharmacodynamic parameters were established for the enantiomers of the 2‐arylpropionic acid (APA) nonsteroidal anti‐inflammatory drug (NSAID), ketoprofen (KTP). Each enantiomer was administered separately (1.5 mg/kg) and in a racemic mixture (3 mg/kg) intravenously (i.v.) to a group of eight sheep in a four‐way, four‐period cross‐over study using a tissue cage model of inflammation. Plasma disposition of each KTP enantiomer was similar following separate administration of the pure compounds compared to administration of the racemic mixture. S(+)KTP volume of distribution (Vdarea) was higher and clearance (ClB) faster than those of R(–)KTP. S(+) and R(–) KTP achieved relatively low concentrations in exudate and transudate. Unidirectional limited chiral inversion of R(–) to S(+)KTP was demonstrated. After R(–)KTP administration S(+)KTP was detected in plasma, but not in either exudate or transudate.Pharmacokinetic/pharmacodynamic (PK/PD) modelling of the data could not be undertaken following R(–)KTP administration because of chiral inversion to S(+)KTP, but the pharmacodynamic parameters, calculated maximum effect (Emax), concentration producing 50% effect (EC50), Hill’s coefficient (N), rate constant of elimination of drug effect from the compartment (KeO) and mean equilibration half‐life (t½Ke0) were determined for S(+)KTP after administration of the racemic mixture as well as the pure compound.
The effect of josamycine on the control of ileitis in weaned piglets under field conditions
Authors: Kyriakis S. C. , Alexopoulos C. , Saoulidis K. , Lekkas S. , Miliotis CH. C. , Sauveroche B. 
Published: March 2003

The effect of josamycine on the control of ileitis in weaned piglets under field conditions.J. vet Pharmacol. Therap.25,279–284.The aim of this trial was to evaluate the effect of in‐feed josamycine on the control of ileitis in weaned piglets. On a farm with a previous history of ileitis outbreaks, 288 piglets at weaning age (25 ± 2 days old) were allocated into three experimental groups, each group comprising of four pens with 24 piglets in each pen. Group one (T1) served the trial as negative control group (unmedicated), group T2 was administered josamycine at 36 mg/kg of feed and group T3 was administered josamycine at 50 mg/kg of feed. Treatments lasted for 14 days followed by an observation period of 28 days. Administration of josamycine at both inclusion levels tested had a beneficial effect compared with the negative control group, by the reduction of prevalence of diarrhoea, the enhancement of growth performance and the reduction of prevalence ofLawsonia intracellularisin the intestine, as determined either by the PCR method or by specific histopathological examinations. The beneficial effect of josamycine was more pronounced at the inclusion level of 50 mg/kg of feed.
The application of GIS‐modelling to mustelid landscape ecology
Authors: Gough Mary C. , Rushton Stephen P. 
Published: March 2003

ABSTRACTLandscapes are mosaics of habitat patches. The composition, configuration and connectivity of these elements changes in space and time as a result of ‘natural’ and human disturbance. Landscapes provide the ecological template for the life history and behavioural processes that determine animal spacing patterns. An understanding of the effects of landscape dynamics on mammal distributions is therefore vital if populations are to be managed effectively. Members of the Mustelidae present a considerable practical and theoretical challenge because of the great range of morphological, behavioural and ecological variation within the family. Habitat use data have been gathered only for a small number of Mustelidae species and most studies have been conducted with few individuals at small spatial scales and over relatively short time spans. Consequently, our knowledge of the landscape ecology of mustelids is very limited. Modelling can provide a strong conceptual framework for investigating mustelid‐habitat relationships. We review the potential of different modelling approaches for analysing the influence of landscape dynamics on the distributions of mustelids.
Sugar meals and longevity of the sandfly Phlebotomus papatasi in an arid focus of Leishmania major in the Jordan Valley
Authors: Schlein Yosef , Jacobson Raymond L. 
Published: March 2003

SummaryThe sugar diet and life‐span of Phlebotomus papatasi were studied in a typical zoonotic focus of Leishmania major in an arid area of the Jordan Valley during 1996–1997. Plant‐tissue residues (cellulose particles) were identified in the stained guts of 23% of P. papatasi and significant amounts of sugar were found in the gut of 16%. Feeding on different plants was demonstrated by using their branches, suffused with cellulose stain, as baits in the field. Ingested, stained cellulose was detected in 10% of the sandflies (6% of males, 12.5% of females) caught near bait‐branches of common local plants, mostly Chenopodiaceae. The similar rates of plant and sugar feeding, with the observed absence of aphids (ruling out the availability of honeydew), implied that the sugar meals of sandflies were obtained directly from plants.The relative paucity of sugar meals in P. papatasi coincided with a short life‐span, evaluated by daily growth lines in the cuticle. The age of the oldest females was estimated to be 8 days, and 6 days for males. Under local conditions, the first gonotrophic cycle can be completed in 6 days and the usual transmission of L. major is apparently afterwards, when females ingest blood to initiate another cycle. Only about 9% of P. papatasi females survived > 6 days.
Molecular and kinetic evidence for allelic variants of esterase Estβ1 in the mosquito Culex quinquefasciatus
Authors: Small G. J. , Karunaratne S. H. P. P. , Chadee D. D. , Hemingway J. 
Published: March 2003

SummaryElevated esterase Estβ1 was purified from larvae of newly isolated strains of the mosquito Culex quinquefasciatus from Colombia (COL) and Trinidad (TRI) with resistance to organophosphate (OP) insecticides. Insecticide interactions were compared with those of elevated Estβ12 from the OP‐resistant Habana strain and the non‐elevated Estβ13 from the susceptible PelSS strain. On the basis of insecticide binding efficiency, all elevated Estβ1 esterases were readily distinguishable. Differences between the EcoRI restriction fragment patterns of the amplified estβ1 gene in COL and TRI strains compared with each other, and between amplified estβ11, estβ12 and the non‐amplified estβ13, suggest differences in their nucleotide sequence. Considering their variable insecticide binding efficiencies, these genetic differences would imply that, in contrast to estα2 and estβ2, amplification of estβ1 has occurred several times independently. Generally, the elevated Estβ1s were more reactive with insecticides than the non‐elevated Estβ13. This supports the hypothesis that the elevated esterase‐based mechanism confers resistance through amplification of alleles coding for esterases which have a greater specificity for the insecticides they sequester than the esterases coded by their non‐amplified counterparts.