bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of mechanical tension on matrix degradation by human periodontal ligament cells cultured in collagen gels
Authors: Von den Hoff J. W.
Published: August 2003

Background:  Periodontal ligament (PDL) cells are thought to play a crucial role in the remodelling of periodontal tissues during orthodontic tooth movement.

Objective:  The objective of this study was to analyse the effects of mechanical tension on matrix degradation by PDL cells cultured in collagen gels.

Methods:  The gels were prepared free‐floating or attached to the culture wells and cultured for up to 22 d. In free‐floating gels very little mechanical tension is generated within the matrix, whereas in attached gels tension is highly increased.

Results:  At d 8, free‐floating gels had contracted to 2% of their original wet weight. Attached gels had contracted to only 40%, but by d 15 all gels had spontaneously detached from the wells and had contracted rapidly. The collagen content of free‐floating gels had decreased to 30% of the initial value at d 22. Collagenase activity was detected in the culture media of the free‐floating gels and the presence of matrix metalloproteinases (MMPs) 2 and 9 was shown by zymography. In addition, histological sections showed matrix degradation around the cells. This shows that ligament cells in free‐floating gels are actively resorbing the collagen matrix. The collagen content of attached gels did not change during the first 8 d but, after detachment, it rapidly decreased to 2%. Therefore, mechanical tension seems to prevent degradation of the matrix. In contrast, relaxation of the tension enhances the resorptive activity.

Conclusions:  The sensitivity of PDL cells to mechanical tension may be essential for the remodelling of periodontal tissues and their adaptation to physiological and orthodontic forces.
A new method for evaluating the threshold of periodontal ligament mechanoreceptor by slow speed mechanical stimulation
Authors: Oki Kazuhiro , Hamanaka Mai , Arima Taro , Takahashi Shuhei , Hasegawa Kouichi , Minagi Shogo
Published: August 2003

Objectives:  This study aimed to establish a reliable method for detecting the threshold for perception of force applied to tooth and to report the basic properties of force threshold in the normal dentition subjects.

Background:  The perception of mechanical stimulation exerted to tooth is formed by input from periodontal ligament mechanoreceptors and intradental mechanoreceptors. Periodontal ligament mechanoreceptors respond to a wide range speed of stimulus, whereas intradental mechanoreceptors are activated only by a rapid stimulation. Reliable properties of perception have not been reported because of the difficulties to regulate velocity and degree of the stimulus.

Methods:  Eighteen healthy subjects were observed in this study (mean age: 27.2 ± 5.7 years). A loading device to generate slow speed loading was fabricated and measured as follows: (i) the fluctuation of the force threshold within a day, (ii) day‐to‐day fluctuation, (iii) changes in the force threshold by a transient mechanical loading.

Results:  In the normal dentition, it was observed that the fluctuation within a day and day to day of the pressure sense showed no significant differences; however, a transient mechanical loading caused the sensitivity of the periodontal ligament to decrease significantly.

Conclusions:  The device examining the force threshold resulted from periodontal ligament mechanoreceptors was useful in evaluating the sensitivity of the periodontal ligament.
Identification of mRNAs for the various diacylglycerol kinase isoforms in neutrophils from patients with localized aggressive periodontitis
Authors: Oyaizu Kosuke , Kantarci Alpdogan , Maeda Hiroshi , L. Batista Eraldo , Hasturk Hatice , Murayama Yoji , Badwey John A. , Van Dyke Thomas E.
Published: August 2003

Background:  Diacylglycerol kinase (DGK) metabolizes diacylglycerol (DAG), an endogenous activator of protein kinase C, to phosphatidic acid. We have previously reported increased DAG in neutrophils from patients with localized aggressive periodontitis (LAP) associated with reduced DGK activity. This reduction could be related to a mutation, post‐translational modification, differential expression, or lack of expression of a particular isoform(s).

Objective:  The aim of this study was to identify the mRNAs for DGK isoforms in normal and LAP neutrophils.

Methods:  The α‐, γ‐, and δ‐isoforms of DGK were identified by polymerase chain reaction (PCR) using specific oligonucleotide primers for each isoform. The PCR products were isolated and sequenced for comparison to published sequences to confirm the validity of the PCR reaction. Total RNA was isolated from LAP and normal neutrophils, and northern blotting and semi‐quantitative reverse transcription polymerase chain reaction (RT‐PCR) was used to examine the level of mRNA for each isoform.

Results:  No major differences were found in the isoform pattern between resting normal and LAP neutrophils. However, the levels of mRNA for the α‐ and γ‐isoforms of DGK were increased in normal neutrophils while slightly decreased in LAP cells upon stimulation with N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP).

Conclusion:  These data suggest that alterations in the mRNAs for the various isoforms of DGK during cell stimulation and the involvement of DGK that is expressed in multiple forms are subject to a variety of regulatory/control mechanisms and these mechanisms may explain the role of the ‘primed’ neutrophil phenotype associated with LAP.
Are there HLA combinations typical supporting for or making resistant against aggressive and/or chronic periodontitis?
Authors: Stein J. , Reichert S. , Gautsch A. , Machulla H. K. G.
Published: August 2003

Objective and background: 
Human leukocyte antigens (HLA)/alleles have been considered as risk factors for periodontal disease. However, data from HLA associations is not consistent. Diversity of HLA antigen combinations and en bloc inherited HLA alleles (haplotypes), as known in systemic diseases, can be variable factors in disease association. Therefore, the aim of this study was to investigate the incidence of HLA homozygosities, heterozygosities and estimated haplotypes in German Caucasian groups with generalized aggressive (N = 50) and chronic (N = 102) periodontitis in comparison to control probands without periodontitis (N = 102).

Methods:  HLA‐A, ‐B, ‐Cw, ‐DRB1, ‐DRB3/4/5, ‐DQB1 typing was carried out using both serologic (microlymphocytotoxicity test) and genomic (PCR‐SSP: PCR with sequence specific primers) techniques. Frequencies of all homozygosities, heterozygosities and haplotypes were determined in all patients and controls.

Results:  In both patient groups, associations to HLA homozygosities and heterozygosities were found. Most striking was the significantly lower frequency of HLA‐DRBblank* homozygosity (non‐DRB3*/DRB4*/DRB5*) in chronic periodontitis (p < 0.05), whereas HLA‐DRB1*15 : DRB5*(DR51) : DQB1*06 showed a slightly higher homozygosity rate in all patients. As the combination HLA‐A*02,A*03 was significantly decreased in aggressive periodontitis (p < 0.05), HLA‐A*01,A*03 heterozygosity was significantly lowered in chronic periodontitis (p < 0.05). Among others, the known positive associations for HLA‐A*68/69 (A28) and HLA‐DRB1*04 were confirmed by the haplotypes HLA‐A*68/69 : Cw*07 : B*18 in aggressive periodontitis (p < 0.05) and HLA‐Cw*08 : B*14 : DRB1*04 in chronic periodontitis (p < 0.05).

Conclusion:  The present study elucidates the variety of HLA associations and therefore the difficulty to assign single HLA markers to periodontal disease. Susceptibility/resistance of both aggressive and chronic periodontitis may rather be influenced by particular HLA marker combinations. Associated HLA haplotypes may be of further importance for unknown gene loci representing a part of the genetic background for periodontitis. The different associations in aggressive and chronic periodontitis indicate different susceptibility/resistance factors for both diseases.
Quantitative real‐time PCR based on single copy gene sequence for detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis
Authors: Morillo Juan M , Lau Laura , Sanz Mariano , Herrera David , Silva Augusto
Published: August 2003

Objective:  To establish a method for quantification of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis from subgingival plaque by real‐time polymerase chain reaction (PCR) technique.

Material and methods:  Bacterial cells from both species were obtained from type culture and counted microscopically. Cellular suspension in sterile destilled water was used for DNA extraction by boiling for 20 min, with a mineral oil cover. Primers for PCR were selected from sequences of LktC gene (A. actinomycetemcomitans) and Arg‐gingipain (P. gingivalis) to yield amplicons below 100 bp. SYBR Green I based real‐time PCR was adjusted to quantify separately both species.

Results:  A good sensitivity and specificity were obtained for both species, although the yield was better for A. actinomycetemcomitans. A good repeatibility of cycle threshold (CT) was encountered, so coefficient of variation was below 6% at every initial copy number.

Conclusion:  A new method of quantification of A. actinomycetemcomitans and P. gingivalis based on SYBR Green real‐time PCR is presented. Its good sensibility and repeatibility will allow its application to analysis of subgingival plaque samples.
Dental root resorption and repair: histology and histometry during physiological drift of rat molars
Authors: Kimura Ryusei , Anan Hisashi , Matsumoto Akiko , Noda Daisuke , Maeda Katsumasa
Published: August 2003

Objective:  The process of dental root resorption and subsequent cementum regeneration has not been sufficiently elucidated. This study aimed to examine the process of the root resorption and cementum regeneration during physiological tooth drift using a rat model, and to evaluate this experimental model.

Methods:  Distal roots in mandibular first molars and the surrounding periodontal tissues were investigated with light and electron microscopy. The light microscopic approach included histochemical and histometric analyses utilizing the tartrate‐resistant acid phosphatase (TRAP) reaction.

Results:  Root resorption was observed in the distal side of the roots and was most active in 5‐ to 6‐week‐old rats, and gradually decreased hereafter. An increase in the number of TRAP‐positive mononuclear cells, which seemed to be odontoclast precursor cells, preceded the increase in the number of odontoclasts. Root resorption was transient, and was followed by the new formation of acellular extrinsic fiber cementum accompanied with only a slight inflammation, and therefore classified as external surface resorption. Preparation for new cementum started adjacent to the resorption areas when root resorption was most active.

Conclusions:  The root resorption during drift in rats is transient and followed by acellular extrinsic fiber cementum regeneration. Cellular kinetics suggested that odontoclast precursor cells are supplied as mononuclear cells from vascular spaces.
Effects of autoclave sterilization on properties of dental rubber dam as related to its use as barrier membrane in guided tissue regeneration
Authors: Apinhasmit Wandee , Limsombutanon Somchai , Swasdison Somporn , Suppipat Nophadol
Published: August 2003

Background and Objective:  Dental rubber dams (RDs) were used as barrier membranes in guided tissue regeneration for the treatment of periodontal intraosseous defects with acceptable clinical results. The aim of the present study was to investigate the effects of autoclave sterilization on properties of RD as related to its use as a barrier membrane in guided tissue regeneration.

Methods:  RDs were sterilized by either an autoclave, gamma irradiation, or chemical agents and then co‐cultured with human gingival fibroblasts. The cell responses to sterilized RDs were investigated by inverted phase contrast microscopy, scanning electron microscopy (SEM) and 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) technique. The surface alterations of the autoclaved RDs were observed under SEM. The tensile strength, tear strength and elongation at break of the autoclaved RDs were tested by a universal testing machine.

Results:  The results from cell culture, microscopic and MTT studies showed that RDs sterilized by autoclave and gamma irradiation did not deteriorate gingival fibroblasts and provided surfaces suitable for cell attachment, whereas chemical‐sterilized RDs were toxic to these cells. Ultrastructurally, surface changes from the non‐autoclaved RDs, including some melted areas, small pores and folds were observed on the autoclaved RD surface. The tensile strength and tear strength of the autoclaved RDs were significantly lower than those of the non‐autoclaved RDs (p = 0.042, p < 0.001, respectively). In contrast, the elongation at break of the autoclaved RDs was higher than that of the non‐autoclaved RDs (p < 0.001).

Conclusion:  These results suggest that the autoclave sterilization deteriorated the physical properties of RDs even though they seemed to be compatible to the cultured human cells. Therefore, the sterilization method should be taken into consideration when RDs are utilized as barrier membranes.
Cancer prevention and therapy: strategies and problems
Authors: Kanduc Darja , Capuano Ferdinando , Capurso Sabrina A. , Geliebter Jan , Guercia Domenico , Lucchese Alberta , Mittelman Abraham , Simone Simone M. , Sinha Animesh A. , Tiwari Raj , Farber Emanuel
Published: August 2003

During the next years, molecular diagnostic science and the pharmaceutical industry will face increasing demand for personalized medicine. Therapeutic treatments should be tailored to the needs of individual patient. Patients will inquire for information about potential tumor detection at an early stage when disease can be more likely to be arrested or cured with specific regimens of drug therapy. To respond to this demand, science and industry need to modulate therapeutic approaches to the continuous development of cancer. Now more than ever, it is necessary to fill the knowledge hiatus between the “beginning” and the “end” of cancer development, i.e we need to critically analyze the extensive multi‐step process of cancer development that still remains poorly understood.
Effects of regulatory domains of specific isoforms of protein kinase C on growth control and apoptosis in MCF‐7 breast cancer cells
Authors: Soh Jae‐Won , Lee Yun‐Sil , Weinstein I. Bernard
Published: August 2003

Protein kinase C (PKC) is a multigene family consisting of at least 11 isoforms that play key roles in growth control and tumorigenesis. To understand the roles of specific isoforms of PKC in breast cancer, we generated derivatives of the human breast cancer cell line MCF‐7 that stably overexpress dominant negative mutants (REG) of PKC‐α, ‐ε, or ‐ζ, which encode only the regulatory domains of the respective isoforms. When stimulated to re‐enter the cell cycle after serum starvation, the MCF‐7/PKC‐α‐REG cell line exhibited enhanced cell‐cycle progression in comparison to the control cell line. These cells also showed increased sensitivity to growth inhibition and induction of apoptosis in response to various cytotoxic stimuli, including serum starvation, tamoxifen, and γ‐radiation. Western blot analysis indicated that the MCF‐7/PKC‐α‐REG cell line displayed marked decreases in the levels of the cyclin‐dependent kinase inhibitor p21CIP1 and the anti‐apoptotic protein bcl‐2. Similar, but less striking, effects were seen in the MCF‐7/PKC‐ε‐REG cell line, and the MCF‐7/PKC‐ζ‐REG cell line showed minimal changes, when compared to the control cells. Taken together, these results suggest that the endogenous PKC‐α in MCF‐7 cells plays a critical role in regulating cell‐cycle control and apoptosis, in part through upregulating the expression of p21CIP1 and bcl‐2. Therefore, inhibitors of PKC‐α may potentiate the activity of cytotoxic agents in the therapy of breast cancer.
Role of snus (oral moist snuff ) in smoking cessation and smoking reduction in Sweden
Authors: Gilljam Hans , Galanti M. Rosaria
Published: August 2003

Aims  To assess to what extent snus has been used as an aid to stop smoking among Swedish smokers.

Design  A random telephone retrospective survey of Swedish smokers and ex‐smokers.

Setting  Survey conducted in November–December 2000.

Participants  A national sample of 1000 former and 985 current daily smokers aged 25–55 years.

Measurements  Smoking status, date and method of quitting by self‐report.

Findings  Thirty‐three per cent of former smokers and 27% of current smokers had ever used snus. The difference was larger among men (55% versus 45%, P = 0.003). Current smokers who made use of snus smoked on average fewer cigarettes per day than non‐users of snus. The mean duration of abstinence among former smokers was not influenced by snus use. Conditionally on age, education and use of nicotine replacement therapy there was an increased probability of being a former rather than a current smoker with ever use (OR 1.72, 95% CI = 1.30–2.28) or current use (OR 1.81, 95% CI = 1.31–2.53) of snus. Having used snus at the latest quit attempt increased the probability of being abstinent by about 50% (OR 1.54, 95% CI = 1.09–2.20).

Conclusions  Our study suggests that by using snus, Swedish male smokers may increase their overall chances of abstinence. However, 71% of the men in this sample who quit smoking did so without using snus and the duration of abstinence was not affected by snus use. This suggests that snus is not a necessary component of smoking cessation at the population level. Snus use was very rare among women.
Should the European Union lift the ban on snus? Evidence from the Swedish experience
Authors: Fagerström Karl Olov , Schildt Elsy‐Britt
Published: August 2003

The very low smoking prevalence in Sweden has received considerable attention. Sweden was the only country in Europe to reach the World Health Organizations’ goal of less than 20% daily smoking prevalence among adults by year 2000. Only 17% of Swedish men smoke. Some have argued that this has been achieved because Swedes use another form of tobacco instead. Sweden has a high level of use of a moist snuff product called ‘snus’. Nineteen per cent of adult men and 1% of women are daily users and the trend is increasing. Epidemiological studies have failed to find evidence that snus causes cancers, including oral cancer. Its adverse effects on the cardiovascular system are debated, but are certainly less than those of smoking. Recent studies among former smokers indicate that many men have quit smoking using snus. Forty‐seven per cent of current snus users are former smokers and 28% of ex‐smoking used snus at their last attempt to stop smoking. The association between high snus consumption and low smoking prevalence has been debated and challenged. It has been argued that snus may be a gateway to cigarette smoking. Recent data has found that among those starting tobacco use in the form of snus, 20% later go on to smoking while the same risk for those not starting with snus is 43%. On balance, there is reason to believe that having snus available to the Swedish population has been of benefit to public health. Repealing the ban on snus in the rest of the European Union might also have some positive effect, depending on the marketing.
Improving self‐reports of drug‐use: numeric estimates as fuzzy sets
Authors: Matt Georg E. , Turingan Maria R. , Dinh Quyen T. , Felsch Julie A. , Hovell Melbourne F. , Gehrman Christine
Published: August 2003

Aims  This study compared traditional crisp set to fuzzy set representations of quantitative estimates of drug use to investigate what survey respondents recall about their drug use.

Design  Sample survey comparing (a) responses to traditional survey questions asking for single numeric estimates to (b) responses to fuzzy set questions asking for boundary estimates of drug use.

Setting  Research facilities of a public university in a large southern California city.

Participants  Community residents using tobacco, alcohol, marijuana or amphetamine (n = 88).

Measurements  Personal interviews in which participants reported onset, frequency and daily rate of tobacco, alcohol, marijuana and amphetamine use based on traditional survey questions and fuzzy set questions.

Findings  With the exception of marijuana use, fuzzy boundary estimates differed significantly from the traditional point estimates (P < 0.05). Median retest reliabilities for fuzzy boundary estimates were 0.96 (tobacco), 0.81 (alcohol), 0.96 (marijuana) and 0.95 (amphetamine). The degree of vagueness varied by behavior and drug, with estimates of daily rates showing greatest fuzziness and onset of use showing least fuzziness.

Conclusions  Participants recall more about past drug use than a single numeric estimate. All numeric estimates of drug use showed fuzzy set properties. Compared to traditional self‐reports of drug use, fuzzy set representations provide a more complete and detailed description of what participants recall about past drug use.
A cross‐national meta‐analysis of alcohol and injury: data from the Emergency Room Collaborative Alcohol Analysis Project (ERCAAP)
Authors: Cherpitel Cheryl J. , Bond Jason , Ye Yu , Borges Guilherme , Macdonald Scott , Giesbrecht Norman
Published: August 2003

Aims  To examine the relationship of acute alcohol consumption with an injury compared to a non‐injury event in the emergency room across ERs in five countries.

Design  Meta‐analysis was used to evaluate the consistency and magnitude of the association of a positive blood alcohol concentration (BAC) at the time of arrival in the ER and self‐reported consumption within 6 hours prior to the event with admission to the ER for an injury compared to a non‐injury, and the extent to which contextual (socio‐cultural and organizational) variables explain effect sizes.

Findings  When controlling for age, gender and drinking five or more drinks on an occasion at least monthly, pooled effect size was significant and of a similar magnitude for both BAC and self‐reported consumption, with those positive on either measure over half as likely again to be admitted to the ER with an injury compared to a medical problem. Effect sizes were found to be homogeneous across ERs for BAC, but not for self‐report. Trauma center status and legal level of intoxication were positively predictive of self‐reported consumption effect size on injury.

Conclusions  These data suggest a moderate, but robust association of a positive BAC and self‐report with admission to the ER with an injury, and that contextual variables also appear to play a role in the alcohol–injury nexus.
Signs of intoxication and server intervention among 18–39‐year‐olds drinking at licensed premises in New South Wales, Australia
Authors: Donnelly Neil , Briscoe Suzanne
Published: August 2003

Aims  To estimate the extent of responsible service of alcohol (RSA) practice to young adults showing signs of alcohol intoxication on licensed premises in New South Wales.

Design  Telephone‐based cross‐sectional survey.

Setting  New South Wales, Australia.

Participants  A total of 1090 people aged 18–39 years old.

Findings  Seventy‐five per cent of males and 64% of females reported that they had consumed at levels for acute alcohol‐related harm during the previous 12 months, with 34% of males and 24% of females reporting doing so weekly; 54% (95% CI: 51–58%) of both males and females who had consumed at acute‐risk levels, reported that this last drinking occasion occurred at a licensed premises. Of these, 56% (95% CI: 51–61%) reported that they had exhibited at least one sign of overt alcohol intoxication, while 19% (95% CI: 15–23%) reported showing three or more signs of intoxication. Among those reporting at least one sign of intoxication, only 10% (95% CI: 7–15%) reported that the licensed premises staff had provided at least one of seven different responsible service initiatives, while 55% (95% CI: 48–61%) reported that they were continued to be served alcohol. While these results suggest that intoxicated patrons are not being refused service as often as they should, there was evidence for some degree of responsible service provision with around half of the ‘non‐intoxicated’ patrons reporting that they had seen licensed premises staff intervene in some way with other ‘intoxicated’ patrons.

Conclusions  While the majority of 18–39‐year‐olds report showing signs of intoxication while drinking at licensed premises in NSW, only a small minority report experiencing RSA initiatives from bar staff in response to these signs.
Prior opiate injection and incarceration history predict injection drug use among inmates
Authors: Calzavara Liviana M. , Burchell Ann N. , Schlossberg Julia , Myers Ted , Escobar Michael , Wallace Evelyn , Major Carol , Strike Carol , Millson Margaret
Published: August 2003

Aims  To describe injection drug use among inmates, and to identify correlates of drug injection while incarcerated.

Design  Cross‐sectional survey.

Setting  Six provincial correctional centres in Ontario, Canada.

Participants  Face‐to‐face interviews were conducted with a random sample of 439 adult males and 158 females.

Measurements  Inmates were asked about drug use in their lifetime, outside the year prior to their current incarceration, and while incarcerated in the past year. Among the 32% (189 / 597) with a prior history of drug injection, independent correlates of injection while incarcerated in the past year were identified using multiple logistic regression.

Findings  Among all inmates while incarcerated in the past year, 45% (269 /597) used drugs and 19% (113 / 596) used non‐cannabis drugs. Among those with a prior history of injecting, 11% (20 / 189) injected while incarcerated in the past year. Rates of injection with used needles were the same pre‐incarceration as they were while incarcerated (32%). Independent correlates of drug injection while incarcerated were injection of heroin (OR = 6.4) or other opiates (OR = 7.9) and not injected with used needles (OR = 0.20) outside in the year prior to incarceration, and ever being incarcerated in a federal prison (OR = 5.3).

Conclusions  The possibility of transmission of human immunodeficiency virus (HIV), hepatitis C (HCV) or other blood‐borne diseases exists in Ontario correctional centres. In this setting, drug injection while incarcerated is primarily related to opiate use prior to incarceration. The correlation between injecting and extensive incarceration history suggests missed opportunities to improve inmates’ health.
What happens to women's self‐reported cigarette consumption and urinary cotinine levels in pregnancy?
Authors: Lawrence Terry , Aveyard Paul , Croghan Emma
Published: August 2003

Aims  To describe the pattern of self‐reported cigarette consumption and nicotine consumption, measured by urinary cotinine concentration, in a cohort of pregnant women who did not stop smoking.

Design  Cohort study.

Setting  Randomly selected general practices from the West Midlands, UK.

Participants  Five hundred and fifty‐nine pregnant women in a clinical trial who were enrolled at booking for maternity care (about 12 weeks of gestation), who were followed up in mid and late pregnancy and 10 days post‐natal and who did not stop smoking during that period.

Measurements  Retrospectively collected self‐reported cigarette consumption prior to pregnancy and contemporaneously collected self‐reported cigarette consumption and urinary cotinine concentrations at booking for maternity care, 20 weeks of gestation, 30 weeks of gestation and 10 days post‐natal.

Findings  Women reported smoking a median of 10–19 cigarettes per day prior to pregnancy and a median of 5–9 cigarettes per day at booking for maternity care. At booking, women reported consuming a mean [95% confidence interval (CI)] of 6.3 (5.6–7.0) cigarettes per day. At 20 weeks of pregnancy this had risen to mean (95% CI) 11.5 (10.9–12.2), and remained at 11 cigarettes per day when measured again at 30 weeks of gestation and 10 days post‐natal. Mean (95% CI) urinary cotinine levels at booking were 6.0 (5.4–6.6) µg/mL, and did not change much through pregnancy. There were statistically significant associations between urinary cotinine and reported cigarette consumption at all time points except at booking.

Conclusions  Women smokers report lower cigarette consumption at booking for maternity care than they do prior to pregnancy or from mid pregnancy onwards, but cotinine data imply that their intake of toxins does not change throughout pregnancy. Reports suggesting many women reduce their smoking in pregnancy have probably been over‐optimistic.
Sporting activity and drug use: alcohol, cigarette and cannabis use among elite student athletes
Authors: Peretti‐Watel Patrick , Guagliardo Valérie , Verger Pierre , Pruvost Jacques , Mignon Patrick , Obadia Yolande
Published: August 2003

Aims  To study the relationship between sporting activity and alcohol, cigarette and cannabis use among adolescents and young adults, by focusing on elite student athletes (ESAs).

Design, setting, subjects  Cross‐sectional survey (Spring 2002), in a sample of 460 ESAs (ages 16–24 years) recruited at 40 public centres gathering the young sporting elite from 30 different sports in South‐Eastern France, comparison with samples of the general population of adolescents in South‐Eastern France.

Measures  Respondents were asked confidentially by a self‐administered questionnaire about their use of licit and illicit drugs, their sporting activity and other aspects of their life‐style.

Findings  Prevalences of cigarette, alcohol and cannabis use were markedly lower for ESAs than for other adolescents (generally twice or three times as low). Among ESAs, when compared with the practice of an individual sport, the practice of a team sport was correlated positively with alcohol use (OR = 2.7 for girls, OR = 1.8 for boys), and the practice of a sliding sport was correlated positively with cannabis use (for girls: OR = 2.3) and with alcohol use (for boys: 4.3). Girls who entered competition at international level were more prone to smoke cigarettes and cannabis (OR = 6.1 and 2.4, respectively).

Conclusions  As a whole, practising sports as an elite student‐athlete can be considered as correlated negatively with cigarette, alcohol and cannabis use. Nevertheless, this relationship depends on the kind of sport practised as well as the level of competition, and further research is needed to understand specific elite athletes’ motives for use.
The pore–solid fractal model of soil density scaling
Authors: Bird N.R.A. , Perrier E.M.A.
Published: August 2003

We have developed the fractal approach to modelling variations in soil bulk density and porosity with scale of measurement or sample size. A new expression is derived for each quantity based on the pore–solid fractal (PSF) model of soil structure. This new general expression covers a range of fractal media and accommodates existing fractal models as special cases. Model outputs cover a range of scaling behaviour expressed in terms of monotonic functions, from increasing density and decreasing porosity, through constant porosity and density to decreasing density and increasing porosity with increasing scale of measurement. We demonstrate the link between this new model for the scaling of porosity and bulk density and the water retention model for the PSF. The model for scaling bulk density is fitted to data on aggregate bulk density and shown to yield good fits describing bulk density decreasing with increasing aggregate size. Porosity scaling is also inferred from the fitting of water retention data. Inferred porosities from different fittings are shown to follow decreasing, scale‐invariant and increasing values with decreasing size of structural unit, and these theoretical results emphasize the need for further experimental investigation on the basic issue of density scaling in soil science.
Modelling carbon and nitrogen dynamics in a bare soil with and without straw incorporation
Authors: Garnier P. , Néel C. , Aita C. , Recous S. , Lafolie F. , Mary B.
Published: August 2003

Incorporating straw into the ploughed layer of soil affects the dynamics of carbon and nitrogen. A precise quantification of its short‐term effect in agricultural fields is difficult because biological and physical processes interact and take place simultaneously. As an alternative to experimentation, investigations have turned to simulations using mechanistic models, and we have taken this approach. The goal of our study was to test a mechanistic and one‐dimensional model of transport and biotransformation (PASTIS) against a data set obtained in a field experiment in northern France. We tested carbon and nitrogen dynamics by measuring C mineralization rates, the rates of gross immobilization and mineralization of N (using 15N tracing), and inorganic pools of N in the soil profile during 1 year in a bare soil with or without addition of wheat straw. Most of the model parameters were determined in independent experiments. We estimated the biological parameters from incubation experiments in the laboratory. The simulated results were in good agreement with experimental data, particularly for gross N rates. Hypotheses concerning the pathway of microbial assimilation and the dependence of decomposition on the size of the biomass were tested. The simulated net N immobilization due to addition of straw (8000 kg dry matter ha−1) reached a maximum of 64 kg N ha−1 after 2 months, whereas the observed value was 66 kg N ha−1. The model indicated that after 13 months the incorporation of straw had reduced the net amount of nitrogen mineralized by 13% and the amount of leached nitrate by 27%. The sensitivity analysis to the depth of straw incorporation indicated that the deeper was the incorporation the less was the leaching and the mineralization of nitrogen.
Dependence of the surface fractal dimension of soil pores on image resolution and magnification
Authors: Dathe A. , Baveye P.
Published: August 2003

Two recent investigations have reported contradictory trends concerning the effect of image resolution on the surface fractal dimension of soil pores, evaluated via image analysis. In one case, dealing with a preferential flow pathway and an ideal fractal, image resolution had no influence on the estimated fractal dimension, whereas in the other case, involving images of soil thin sections, the surface fractal dimension decreased significantly with image resolution. In the present paper, we try to determine the extent to which these conflicting observations may have been due to the different ways in which image resolution was varied. By narrowing down (up to 400 times) the field of view on progressively smaller portions of a textbook surface fractal, the von Koch island, one causes its apparent surface fractal dimension to decrease significantly. On the other hand, changing the resolution of images of soil thin sections (up to 6 times), while keeping the magnification constant, does not lead to appreciable changes in the surface fractal dimension. These results demonstrate that there is no real conflict in earlier reports, as long as both the resolution and the magnification of images are taken into account in image‐based evaluations of surface fractal dimensions of soil pores.
Measuring N2O emissions from organic soils by closed chamber or soil/snow N2O gradient methods
Authors: Maljanen M. , Liikanen A. , Silvola J. , Martikainen P. J.
Published: August 2003

Drained organic soils contribute substantial amounts of nitrous oxide to the global atmosphere, and we should be able to estimate this contribution. We have investigated when the fluxes of N2O from drained forested or cultivated organic soils could be determined by calculating the fluxes from the concentration gradients of the gas in soil or snow according to Fick's law of diffusion. A static chamber method was applied as a control technique for the gas gradient method. Concentrations of N2O in soil varied from 296 nl l−1 to 8534 nl l−1 during the snow‐free periods and were greatest in the early summer. Our results suggest that the gas gradient method can be used to estimate N2O emissions from drained organic soils. There was some systematic difference in the N2O fluxes measured with these two methods, which we attributed to the differences in weather between years 1996 and 1997. In the wet summer of 1996 the chamber method gave greater flux rates than the gas gradient method, and the reverse was true in the dry summer of 1997. In the forest the N2O fluxes measured with the two methods agreed well. The gas gradient is convenient and fast for measuring N2O emissions from fairly dry organic unfrozen soil. In winter the diffusion calculation based on the N2O gradients in snow and the chamber method gave fairly similar flux rates and provided adequate estimates of the fluxes of N2O in winter.
Effects of flooding and redox conditions on solute diffusion in soil
Authors: Kirk G. J. D. , Solivas J. L. , Alberto M. C.
Published: August 2003

Rates of solute diffusion fundamentally affect the properties of flooded soils, but the effects of flooding on solute diffusion have not previously been studied in detail. Four soils with widely differing chemical and physical properties were packed to a range of bulk densities, flooded for varying times, and the self‐diffusion of chloride through the soils measured. Diffusion impedance factors were derived from the results. In each soil the impedance factor decreased linearly with increase in bulk density, and between soils impedance factors increased with increasing clay content. The impedance factor decreased by up to 20% during the first 3–6 weeks following flooding, but with prolonged flooding it increased to at least its initial value. Concomitantly the cation exchange capacities of the soils increased by between 30 and 100%, there was reductive dissolution of soil iron, probably both structural iron in soil clays and iron oxyhydroxide coatings on clay surfaces, and subsequently there was re‐precipitation of ferrous iron, probably as mixed carbonates and hydroxides. The decreases in diffusion impedance factors were consistent with the increases in cation exchange capacity and changes in soil iron, and the subsequent increases were consistent with re‐crystallization of mixed ferrous–ferric compounds. We conclude that the effects of changes in redox on diffusion impedance will be important in some soils, although they are smaller than the effects of water content per se.
Mass fractal dimension of soil macropores using computed tomography: from the box‐counting to the cube‐counting algorithm
Authors: Perret J.S. , Prasher S.O. , Kacimov A.R.
Published: August 2003

Transport phenomena in porous media depend strongly on three‐dimensional pore structures. Macropore networks enable water and solute to move preferentially through the vadose zone. A complete representation of their geometry is important for understanding soil behaviour such as preferential flow. Once we know the geometrical, topological and scaling attributes of preferential flow paths, we can begin computer simulations of water movement in the soil.

The box‐counting method is used in three dimensions (i.e. cube‐counting algorithm) to characterize the mass fractal dimension of macropore networks using X‐ray computed tomography (CT) matrices. We developed an algorithm to investigate the mass fractal dimension in three dimensions and to see how it compares with the co‐dimensions obtained using the box‐counting technique in two dimensions. For that purpose, macropore networks in four large undisturbed soil columns (850 mm × 77 mm diameter) were quantified and visualized, in both two and three dimensions, using X‐ray CT. We observed an increasing trend between the fractal dimension and macroporosity for the four columns. Moreover, similar natural logarithm functions were obtained for the four cores by a least squares fit through plots of mass fractal dimension against macroporosity.
Transcriptional control for initiation of chromosomal replication in Escherichia coli: fluctuation of the level of origin transcription ensures timely initiation
Authors: Su’etsugu Masayuki , Emoto Akiko , Fujimitsu Kazuyuki , Keyamura Kenji , Katayama Tsutomu
Published: August 2003

Background:  During the cell cycle, the initiation of chromosomal replication is strictly controlled. In Escherichia coli, the initiator DnaA and the replication origin oriC are major targets for this regulation. Here, we assessed the role of transcription of the mioC gene, which reads through the adjacent oriC region. This mioC‐oriC transcription is regulated in coordination with the replication cycle so that it is activated after initiation and repressed before initiation.

Results:  We isolated a strain bearing a mioC promoter mutation that causes constitutive mioC‐oriC transcription from the chromosome. A quantitative S1 nuclease assay indicated that in this mutant, the level of transcription does not fluctuate. Introduction of this mutation suppressed the growth defect of an overinitiation‐type dnaAcos mutant, and severely inhibited the growth of initiation‐defective dnaA mutants at semipermissive temperatures in a dnaA allele‐specific manner. These results suggest that mioC‐oriC transcription inhibits initiation at oriC. Indeed, flow cytometry analysis and quantification of DNA replication in synchronized cultures revealed that the mioC promoter mutation alters the control of the initiation of chromosomal replication, for instance by delaying replication within the cell cycle.

Conclusions:  These results suggest that the transcriptional regulation of the mioC gene is required for cell cycle‐coordinated initiation of chromosomal replication.
Identification and characterization of a novel progesterone receptor‐binding element in the mouse prostaglandin E receptor subtype EP2 gene
Authors: Tsuchiya Sohken , Tanaka Satoshi , Sugimoto Yukihiko , Katsuyama Masato , Ikegami Reiko , Ichikawa Atsushi
Published: August 2003

Background:  Gene expression of prostaglandin E receptor EP2 is induced in the luminal epithelium of the mouse uterus during peri‐implantation period (day‐5 of pseudopregnancy), suggesting the involvement of progesterone and its receptor (PR) in this expression. However it remains unclear whether PR affects EP2 gene expression through its binding.

Results:  We investigated transcriptional regulation of EP2 gene expression with reporter gene analysis using HeLa cells with or without expression of the PR. The 5′‐flanking region (−3260 to −27, upstream of the translation initiation site) exhibited progesterone‐induced promoter activation and basal promoter activity in the presence of PR. Using successive deletion analysis, we determined the six regulatory regions in the EP2 gene. Three regions were found to be involved in progesterone‐induced promoter activation, whereas the other three regions were involved in basal promoter activity in the presence of PR. We identified a novel PR‐binding sequence, 5′‐G(G/A)CCGGA‐3′, in the two basal promoter regions and Sp1‐ and Sp3‐binding in the other basal promoter region.

Conclusions:  We identified a novel PR‐binding sequence, which may be involved in the regulation of basal promoter activity in the EP2 gene.
Ethics of information giving: the librarian's view*
Authors: TABOR R. B.
Published: August 2003

The American Library Association's Statement on Professional Ethics and the Library Association's Code of Professional Conduct are discussed with particular reference to the responsibilities of librarians working within the context of the National Health Service.
A transcontinental job exchange
Authors: FLAKE DONNA , BELL JO ANN , STONE OREN M. , KING T. A.
Published: August 2003

A staff exchange is described between an English and a U.S. medical librarian. It ran for six months and the librarians exchanged jobs, houses and cars but not salaries. The expectations and benefits of this international job exchange are explored from the differing points of view of the exchange partners and the library directors. For its value as staff development it was worthwhile not only for the partners but also for those colleagues who were involved.
The status and development of online information retrieval in the biomedical field in Czechoslovakia
Authors: WELCH JACQUELINE
Published: August 2003

An account is given of a visit to Czechoslovakia under the auspices of the British Council. The purpose was to explore the status of online information retrieval in the biomedical field and to promote the exchange of ideas, experience and expertise with medical librarians in Czechoslovakia working in this area. Details are given of the services available in Czechoslovakia and comparisons are drawn between provision there and in the U.K. The cultural and social facilities are also described.
Performance indicators in the Oxford Region Library and Information Service: first steps
Authors: VAN LOO JOHN
Published: August 2003

This article outlines the results of a first attempt in the Oxford Regional Health Authority to establish performance indicators for NHS libraries. Thirteen data elements and 11 ratios of performance are described, along with the data themselves for the libraries in seven District Health Authorities.
Pre‐registration training in health‐care libraries.
Authors: HEWLETT JOHN
Published: August 2003

This check‐list is intended to be used for self‐assessment for newly qualified librarians during the pre‐registration period; it will also be useful for experienced librarians who undertake the supervision and training of newly qualified library staff.
Planning for the future?
Authors: TABOR ROY B.
Published: August 2003

Will we see the development of a World Health Knowledge Base and how will the NLM long‐range plan affect the future delivery of biomedical information? The following contributions consider these questions. The important and changing role of health information professionals is emphasized.
Medical audit and libraries—an opportunity for progress
Authors: PADDEN SHEILA C. R.
Published: August 2003

Working for patients has necessitated the use of medical audit as a quality assurance tool. This paper presents an overview of the form and content of audit, and examines the supporting role of the library. It notes the failure of many Regional Medical Audit Implementation Plans to recognize the value of library services, and proposes a strategy to enable librarians to play an active part in the process, and by doing so to increase awareness of library services and improve decision making.
Getting together with compact disc: a regional medline cd‐rom initiative for libraries
Authors: WENTZ R. , WHITSED N.
Published: August 2003

An initiative by the North West Thames Regional Information Technology Agency has resulted in the provision of some 30 cd‐rom drives and copies of the medline database in National Health Service libraries. The development of the scheme and its implementation are described and future developments outlined.
Survey of library and information use by health‐care students
Authors: WALTON GRAHAM , BISSESSUR RAAJ , COOPER ROZ
Published: August 2003

The study compares and contrasts the usage and views of three groups of health‐care students (Pre‐Project 2000, Project 2000 and BSc Occupational Therapy) on their library facilities. A literature review is included which underpins the importance of libraries for health‐care students. Data was compiled from survey responses. The results demonstrate which libraries the students use, how often they use them, what they do in the libraries, and the stock used. They also show the level of student confidence and the services used. The implications of the study for future provision are considered.