Efficacy of sonically, ultrasonically and laser-activated irrigation in removing a biofilm-mimicking hydrogel from an isthmus model.

AIM: To evaluate the efficacy of sonically, ultrasonically and laser-activated irrigation (LAI) in removing a biofilm-mimicking hydrogel from the isthmus in a root canal model. METHODOLOGY: Transparent resin blocks containing two standardized root canals (apical diameter of 0.3 mm, 6% taper, 16 mm long, with a coronal reservoir) connected by an isthmus (0.15 mm wide, 2 mm high) were used as the test model. The isthmus was filled with a hydrogel-containing dentine debris. The canals were filled with irrigant, and the models were randomly assigned to the following activation groups (n = 20): EndoActivator (EA), Eddy, ultrasonically activated irrigation (UAI) with an Irrisafe 25 mm length, size 25 file and LAI with a 2940 nm Er:YAG-laser (20 Hz, 50 µs, 20 mJ, PIPS tip at the canal entrance). All protocols were executed for 3 × 20 s. Needle irrigation (NI) with a 27G needle served as the control. Standardized images of the isthmus were taken before and after irrigation, and the amount of removed hydrogel was determined using image analysis software and compared across groups using Welch anova (P ≤ 0.05). RESULTS: Hydrogel removal was greatest in the LAI group (90.2%) and was significantly greater than that with UAI, EA and NI (P ≤ 0.014), but not significantly different from Eddy (P = 0.498). Hydrogel removal with Eddy (85.9%) was significantly greater than that with NI and EA (P < 0.05), but not significantly different from UAI (P = 0.07). There was no significant difference between the NI and EA groups (P = 1). CONCLUSIONS: Laser-activated irrigation and Eddy resulted in the greatest hydrogel removal and performed better than EA and UAI. The effect of LAI was also not dependent on deep intracanal tip placement.

The external phenotype-skeleton link in post-hatch farmed Chinook salmon (Oncorhynchus tshawytscha).

Skeletal deformities in farmed fish are a recurrent problem. External malformations are easily recognized, but there is little information on how external malformations relate to malformations of the axial skeleton: the external phenotype-skeleton link. Here, this link is studied in post-hatch to first-feed life stages of Chinook salmon (Oncorhynchus tshawytscha) raised at 4, 8 and 12°C. Specimens were whole-mount-stained for cartilage and bone, and analysed by histology. In all temperature groups, externally normal specimens can have internal malformations, predominantly fused vertebral centra. Conversely, externally malformed fish usually display internal malformations. Externally curled animals typically have malformed haemal and neural arches. External malformations affecting a single region (tail malformation and bent neck) relate to malformed notochords and early fusion of fused vertebral centra. The frequencies of internal malformations in both externally normal and malformed specimens show a U-shaped response, with lowest frequency in 8°C specimens. The fused vertebral centra that occur in externally normal specimens represent a malformation that can be contained and could be carried through into harvest size animals. This study highlights the relationship between external phenotype and axial skeleton and may help to set the framework for the early identification of skeletal malformations on fish farms.

Vertebral column regionalisation in Chinook salmon, Oncorhynchus tshawytscha.

Teleost vertebral centra are often similar in size and shape, but vertebral-associated elements, i.e. neural arches, haemal arches and ribs, show regional differences. Here we examine how the presence, absence and specific anatomical and histological characters of vertebral centra-associated elements can be used to define vertebral column regions in juvenile Chinook salmon (Oncorhynchus tshawytscha). To investigate if the presence of regions within the vertebral column is independent of temperature, animals raised at 8 and 12 °C were studied at 1400 and 1530 degreedays, in the freshwater phase of the life cycle. Anatomy and composition of the skeletal tissues of the vertebral column were analysed using Alizarin red S whole-mount staining and histological sections. Six regions, termed I-VI, are recognised in the vertebral column of specimens of both temperature groups. Postcranial vertebrae (region I) carry neural arches and parapophyses but lack ribs. Abdominal vertebrae (region II) carry neural arches and ribs that articulate with parapophyses. Elastic- and fibrohyaline cartilage and Sharpey's fibres connect the bone of the parapophyses to the bone of the ribs. In the transitional region (III) vertebrae carry neural arches and parapophyses change stepwise into haemal arches. Ribs decrease in size, anterior to posterior. Vestigial ribs remain attached to the haemal arches with Sharpey's fibres. Caudal vertebrae (region IV) carry neural and haemal arches and spines. Basidorsals and basiventrals are small and surrounded by cancellous bone. Preural vertebrae (region V) carry neural and haemal arches with modified neural and haemal spines to support the caudal fin. Ural vertebrae (region VI) carry hypurals and epurals that represent modified haemal and neural arches and spines, respectively. The postcranial and transitional vertebrae and their respective characters are usually recognised, but should be considered as regions within the vertebral column of teleosts because of their distinctive morphological characters. While the number of vertebrae within each region can vary, each of the six regions is recognised in specimens of both temperature groups. This refined identification of regionalisation in the vertebral column of Chinook salmon can help to address evolutionary developmental and functional questions, and to support applied research into this farmed species.

Differential Expression of the Arabidopsis 2S Albumin Genes and the Effect of Increasing Gene Family Size.

We studied the expression of the four genes encoding 2S albumin seed storage proteins (at2S1 to at2S4) in Arabidopsis thaliana. All four genes followed similar temporal profiles throughout development, but at2S2 and at2S3 were expressed at significantly higher levels than at2S1 or at2S4. In situ hybridization showed that at2S2 to at2S4 mRNAs were present throughout the embryo, whereas at2S1 was expressed at levels similar to at2S2 and at2S3 in the embryo axis but at only insignificant levels in the cotyledons. The different members of the gene family are, thus, likely to be regulated by different combinations of cis-acting elements, but it cannot be ruled out that post-transcriptional factors play a role. We studied the effect of enlarging the gene family by introducing an extra, nearly identical gene driven by the promoter of at2S1. The data were consistent with a model in which the expression of at2S2 to at2S4 is not affected by that of at2S1, and in which, at least at low copy numbers of the introduced gene, there is no limit on the overall amount of RNA that the at2S gene family can produce.

Pd surface and Pt subsurface segregation in Pt1-c Pd c nanoalloys.

The structure and chemical arrangement of Pt1-c Pd c nanoalloys with the icosahedral and face centered cubic symmetry are studied using Monte Carlo simulations with a tight binding interatomic potential fitted to density-functional theory calculations. Pd surface segregation from the lowest to the highest coordinated sites is predicted by the theory together with a Pt enrichment at the subsurface, whatever the structure and the size of the nanoparticles, and which subsists when increasing the temperature. The onion-shell chemical configuration is found for both symmetries and is initiated from the Pd surface segregation. It is amplified in the icosahedral symmetry and small sizes but when considering larger sizes, the oscillating segregation profile occurs near the surface on about three to four shells whatever the structure. Pd segregation results from the significant lower cohesive energy of Pd as compared to Pt and the weak ordering tendency leads to the Pt subsurface segregation. The very weak size mismatch does not prevent the bigger atoms (Pt) from occupying subsurface sites which are in compression whereas the smaller ones (Pd) occupy the central site of the icosahedra where the compression is an order of magnitude higher.

A cohort study of factors associated with failure to return for HIV post-test counselling in pregnant women: Kigali, Rwanda, 1992-1993.

OBJECTIVE: To identify factors associated with failure to return for HIV post-test counselling in pregnant women in Kigali (Rwanda). SUBJECTS AND METHODS: In the context of a study on the impact of HIV infection on pregnancy, HIV-1-antibody testing was offered to all pregnant women attending the antenatal clinic of the Centre Hospitalier de Kigali from July 1992 to August 1993. Pre-test counselling was performed after verbal informed consent was obtained. Two weeks later, we formally enrolled all HIV-positive women and a corresponding number of HIV-negative women in a cohort. At this visit, post-test counselling was given to those wishing to be informed of their HIV serostatus. Level of knowledge about modes of HIV transmission and condom use were recorded. Four months after delivery, another interview was conducted to determine the proportion of women who used condoms regularly. RESULTS: A total of 1233 pregnant women were screened. The HIV seroprevalence was 34.4% [95% confidence interval (CI), 31.7-37.1]; 271 (63.9%) out of 424 HIV-positive and 577 (71.3%) out of 809 HIV-negative women asked for their HIV serostatus (P = 0.008). In multivariate analysis, the only variable significantly associated with failure to return for post-test counselling was a positive HIV test result (odds ratio, 0.7; 95% CI, 0.5-0.9; P = 0.009), independently of obstetrical history and socioeconomic characteristics. Among the 848 women who had post-test counselling, 50.9% of the HIV-positive women and 94.6% of the HIV-negative women stated that they planned to inform their partner of their serostatus (P = 0.0001). More than 95% of the women interviewed knew about sexual and parenteral transmission of HIV, but half were unaware of mother-to-child transmission. More than 80% of the women had seen a condom before, but 14% only had used it at least once. Among women who were sexually active 4 months after delivery, 8.8% of the HIV-positive and 3.9% of the HIV-negative women reported using a condom (P = 0.04). CONCLUSION: Innovative approaches for HIV testing and counselling programs are needed and the importance of psychosocial and cultural factors associated with HIV testing should be emphasized in African populations.

Perinatal transmission of HIV-1: lack of impact of maternal HIV infection on characteristics of livebirths and on neonatal mortality in Kigali, Rwanda.

We present the baseline results of a prospective cohort study on the perinatal transmission of HIV-1 in Kigali, Rwanda. HIV-1-antibody testing was offered to all women of urban origin delivering a live newborn at the maternity ward of the Centre Hospitalier de Kigali from November 1988 to June 1989; 218 newborns of 215 HIV-positive mothers were matched to 218 newborns of 216 HIV-negative mothers. The matching criteria were maternal age and parity. No differences in socioeconomic characteristics were observed between HIV-positive and HIV-negative women. HIV-positive mothers more frequently reported a history of at least one death of a previously born child (P less than 0.01) and a history of abortion (P less than 0.001). Most of the HIV-positive women were asymptomatic, but 72.4% of them had a CD4; CD8 ratio less than 1 versus 10.1% in the HIV-negative group (P less than 0.001). The frequency of signs and symptoms was not statistically different in the two groups, except for a history of herpes zoster or chronic cough, which was more frequent among HIV-positive women. The rates of prematurity, low birth weight, congenital malformations and neonatal mortality were comparable in the two groups. However, infants of HIV-positive mothers had a mean birth weight 130 g lower than the infants of HIV-negative mothers (P less than 0.01). The impact of maternal HIV-1 infection on the infant seems limited during the neonatal period.

Effect of HIV-1 infection on pregnancy outcome in women in Kigali, Rwanda, 1992-1994. Pregnancy and HIV Study Group.

OBJECTIVE: To study the effect of HIV-1 infection on pregnancy outcome in women provided with antenatal services including malaria and sexually transmitted disease (STD) treatment in Kigali, Rwanda. SUBJECTS AND METHODS: Pregnant women attending the antenatal clinic ward of the Centre Hospitalier de Kigali in their last 3 months of pregnancy were tested for HIV antibody after consent had been obtained. All HIV-1-infected women were included and compared with HIV-negative women of same age and parity. Until delivery, each woman enrolled had a monthly follow-up including malaria and STD aetiological diagnosis and treatment. At the time of delivery, obstetrical and neonatal characteristics were recorded. Mothers and their children were followed until 6 weeks postpartum. RESULTS: By mid-August 1993, 384 HIV-positive and 381 HIV-negative women had been enrolled and by the end of November 1993, 729 women (95.3%; 364 HIV-positive and 365 HIV-negative) had delivered 725 livebirths, including eight and six twins, respectively; 10 stillbirths were recorded amongst HIV-positive women and eight amongst HIV-negative women (P=0.60). Excluding twins, premature birth (< 37 completed weeks of gestation) was observed in 22.7% of infants born to HIV-positive women versus 14.1% of those born to HIV-negative women; low birth weight (< 2500 g) was observed in 25.5% of infants born to HIV-positive women versus 14.8% of those born to HIV-negative women. Low birth weight was significantly more frequent in full-term infants born to HIV-positive mothers than to HIV-negative mothers. No significant difference in low birth weight rate was observed in preterm infants. Death occurred in 5.1% of children during the perinatal period without statistically significant difference between the two groups. HIV-positive women were more likely to have a postpartum haemorrhage. CONCLUSION: In the context of high HIV prevalence, maternal HIV infection is associated with adverse obstetrical and neonatal outcomes even when treating STD and malaria.

Pregnancy, body weight and human immunodeficiency virus infection in African women: a prospective cohort study in Kigali (Rwanda), 1992-1994. Pregnancy and HIV Study Group (EGE).

OBJECTIVE: To study the relationship between human immunodeficiency virus (HIV) infection and body weight in African women during and after pregnancy. METHODS: A prospective cohort study was initiated at the Centre Hospitalier de Kigali in July 1992. Every woman seen at the antenatal clinic and with a gestational age of <28 weeks was offered HIV-1 antibody testing. Comparable numbers of HIV-infected (HIV+) and uninfected (HIV-) women were recruited. At inclusion, socio-demographic characteristics and self-reported pre-pregnancy weight were recorded; height and weight were measured. Each woman enrolled had a monthly follow-up until 9 months after delivery, with a clinical examination including weighing. Three anthropometric indices were used to answer the study objectives: weight, body mass index (BMI), and pregnancy balance. RESULTS: As of April 1994, 101 HIV+ and 106 HIV- women were followed until 5 months after delivery. Weight and BMI during pregnancy were lower in HIV+ women than in HIV- women. After delivery, weight and BMI gains were significantly lower in HIV+ women. Until 5 months after delivery, the mean weight variation was -2.2 kg (standard deviation [SD] = 5.9 kg) in HIV+ women and +0.2 kg (SD = 6.6 kg) in HIV- women (P = 0.007) in comparison to pre-pregnancy weight. Comparisons of the slopes of the weight curves did not show statistical differences throughout the pregnancy, but it did during the post-partum period (P = 0.02). CONCLUSIONS: Our study suggests that HIV infection could impair nutritional status in pregnant women, especially during the post-partum period. Family planning and maternal and child health services including HIV testing and counselling, should consider a nutritional assessment and intervention programme targeted to HIV+ pregnant women.

Birthweight and socioeconomic status: a study in Kigali, Rwanda.

Data were collected on 6709 singleton livebirths occurring in the hospital of Kigali, Rwanda. An analysis of birthweights was carried out by socioeconomic status, parity and age of the mother. The mean birthweight was highest in the high socioeconomic group. An effect of maternal age and parity on birthweight was observed. Because of the strong association between socioeconomic status and birthweight, the incidence of low birthweight can be used as an indicator of socioeconomic development.

PIP: The association between birthweight and socioeconomic status was investigated in the 6707 singleton births that occurred in the hospital in Kigali, Rwanda, in a 2-year period. Socioeconomic status was defined according to whether the mother delivered at the fee-paying clinic (high group) or at the free public clinic (low group). To evaluate the effect of parity, the birthweight data were given separately for 1st-born children and 4th-born children. In addition, primiparae were divided into 2 groups: mothers younger than 20 years of age and those age 20 years and older. Overall, the incidence of low birthweight (under 2500 grams) was 17.5% in this survey. Before analyzing for socioeconomic status, the percentage of low birthweight infants in the 3 age/parity categories was: para 1, under 20 years, 28.9%; para 1, 20 years or over, 21.9%; and para 4, 12.0%. Women of the higher socioeconomic group delivered heavier infants than women of the lower group. The difference between the 2 socioeconomic groups was significant at the p0.001 level for the study group as a whole as for the different subgroups. Mean birthweight was 3.12 + or - 0.50 in the high socioeconomic group compared with 2.95 + or - 0.49 in the low socioeconomic group; the percentage of low birthweight infants was 11.5% in the former group and 18.9% in the latter group. Given the strong association observed in this study, it is suggested that the incidence of low birthweight can be used as an indicator of socioeconomic development.

[Placental infection in Rwanda: comparison an HIV infected population and a control population]. / Infection placentaire au Rwanda: comparaison entre une population infectée par le VIH et une population contrôle.

We report an histological study from term placentas of 286 HIV positive women born in Rwanda. We observed chorioamnionitis without any pathogen in 15% of the cases, cocci Gram positive infection in 12 observations and malaria infection in 75% of placentas. We noted 71 cases of active malaria infection with Plasmodium falciparum trophozoites in the erythrocytes of the intervillous spaces, and 135 cases of chronic infection with malaria pigment without any parasite. An ultrastructural study performed in 8 cases of active malaria infection showed characteristic features of trophozoites and schizontes, and malaria pigment. No viral particle were seen. We did not observe any significative difference concerning the incidence of chorioamnionitis and of malaria infection in 275 HIV negative placentas. In the literature as well as in the present study, the main lesions observed in the placentas of AIDS patients were chorioamnionitis. Opportunistic infections and neoplasias of the placenta are exceptional. Detection of HIV proteins by immunochemistry or in situ hybridization is possible, but the HIV could not be identified in the trophoblast by electron microscopy. Mechanisms of the materno-fetal transmission for HIV are currently unknown.

The effects of parental presence upon the facial expression of pain: the moderating role of child pain catastrophizing.

This experiment investigated the effects of child catastrophic thinking and parental presence on the facial expressions of children when experiencing pain. School children experienced pressure pain in either one of two conditions: (1) when observed by a parent (n=53 children and their parent), or (2) when observed by an adult stranger (n=31 children). Analyses revealed that children showed more facial pain expression in the presence of their parent than in the presence of the stranger. This effect was, however, only found for children with infrequent catastrophic thoughts about pain. Children who have frequent catastrophic thoughts expressed high pain regardless of who they believed was observing them. Results are discussed in terms of the social consequences of pain catastrophizing, and the variables contributing to the expression or suppression of pain display in children and its impact upon others.

An inexpensive system for measuring the processing of relational information by romantic partners.

The present paper describes the computer aspects of a reaction time experiment with couples. The hardware consists of two computers connected through a local area network. Issues that deal with the first PC include timing routines, screen control, mice data decoding, and synchronization of computer software--written in Assembler for a PC without hard disk--with information presented in a videotape. The second computer was used for data processing that was written in VBA. Although the system was created for a dedicated purpose, it is easily applicable to other environments.

EPA2000: a multilingual, programmable computer assessment of off-line metacognition in children with mathematical-learning disabilities.

EPA2000 is a program for the assessment of off-line measured metacognitive skills and arithmetical performances in primary school children with mathematical-learning disabilities. The program is designed as a script engine. The concept makes it possible to modify and translate the test into different languages without reprogramming. A user-friendly script editor is built-in, with which all of the parameters of the test can be modified and translated in different languages.

VIDANN: a video annotation system.

VIDANN is a computer program that allows participants to watch a video on a standard TV and to write their annotations (thought/feeling entries) on paper attached to a writing tablet. The system is designed as a Microsoft ActiveX module. It can be further adapted by the individual researcher through the use of a VBScript. All data, including the participant's handwriting, are stored in an XML database. An accompanying Wizard has been designed that enables researchers to generate VBScripts for standard configurations.

Ovarian actinomycosis during first-trimester pregnancy.

A case of actinomycotic ovarian abscess ruptured during early gestation and related to IUD use is reported. The patient was treated by antibiotic therapy and oophorectomy. Further evolution of the pregnancy was irrelevant.