Population Dynamics of Streptococcus mitis in Its Natural Habitat

The purpose of this study was to examine the genetic structure of the typical commensal Streptococcus mitis biovar 1 in its natural habitat in the human oral cavity and pharynx and to investigate the role that selected microbial properties and host, spatial, and temporal factors play in determining the structure of the bacterial population. Consecutive samples were collected from buccal and pharyngeal mucosal surfaces of two infants, their four parents, and two elderly individuals over a period of approximately 1 year. A total of 751 isolates identified as S. mitis biovar 1 were typed by restriction endonuclease analysis (REA) and representative clones were typed by multilocus enzyme electrophoresis (MLEE). The genetic diversity of the S. mitis biovar 1 isolates collected from single infant hosts over a period of 9 to 10 months was found to be between 0.69 and 0.76, which is considerably higher than that previously observed for intestinal populations of Escherichia coli. The study provides evidence of the existence of both transient and persistent clones in adult individuals. In the two infants, however, none of 42 demonstrated clones were detected on more than a single occasion. Statistical calculations showed that the ability to persist was not distributed at random in the S. mitis biovar 1 population. However, neither immunoglobulin A1 protease activity nor the ability to bind alpha-amylase from saliva was a preferential characteristic of persistent genotypes. In contrast to current concepts of climax ecosystems, the species niche in the habitat appears to be maintained predominantly by a succession of clones rather than by stable strains. Several lines of evidence suggest that the major origin of "new" clones is the many other habitats in the respiratory tract that are occupied by this species.     

The effect of dietary n-3 fatty acids on serum concentrations of C-reactive protein: a dose-response study

C-reactive protein (CRP) is a sensitive marker for low-grade inflammation. Long-chain n-3 polyunsaturated fatty acids (PUFA) have anti-inflammatory effects. The objective of the present study was to investigate the effect on serum levels of CRP of n-3 PUFA at two different doses. We also investigated correlations between CRP and the cellular contents of PUFA. Sixty healthy volunteers (twenty-five women and thirty-five men) were randomly assigned to three treatment groups in a double-blind design. The subjects received a supplement of either 6.6 g n-3 PUFA/d, 2.0 g n-3 PUFA/d or placebo (olive oil) for 12 weeks. CRP was measured using a highly sensitive assay. The median serum CRP concentration was 0.78 mg/l. No significant correlations were found between CRP and the content of n-3 PUFA in granulocytes or platelets. Subjects receiving n-3 PUFA had a significant (P<0.01) increase in the cellular contents of 20 : 5n-3, 22 : 5n-3 and 22 : 6n-3, with the largest increase occurring in the group receiving 6.6 g PUFA/d. A significant (P<0.01) decrease in cellular content of 18 : 2n-6 and 20 : 4n-6 was observed simultaneously. Serum CRP concentrations, however, were unaffected by the PUFA-containing supplements. The present study shows that dietary supplementation with PUFA-containing supplements has no effect on serum concentrations of CRP, measured with a highly sensitive assay, in healthy subjects.     

Cardiac computed tomography-verified right ventricular lead position and outcomes in cardiac resynchronization therapy

Journal of Interventional Cardiac Electrophysiology - To evaluate the association between different right ventricular (RV) lead positions as assessed by cardiac computed tomography (CT) and...     

Molecular cytogenetic analysis of a nontumorigenic human breast epithelial cell line that eventually turns tumorigenic: Validation of an analytical approach combining karyotyping,comparative genomic hybridization,chromosome painting,and single-locus fluorescence in situ hybridization

The immortalized, nontumorigenic human breast epithelial cell line HMT-3522 has been used as a model for premalignant and, eventually, malignant development. During cultivation, the karyotype evolution was followed. At an early stage, a very long constant phase showed a near-diploid karyotype, with only five marker chromosomes. DNA from this phase was used for comparative genomic hybridization (CGH) analysis, confirming a previously known MYC amplification, and the integration sites were subsequently determined by single-locus fluorescence in situ hybridization (FISH). Furthermore, gains of 5q22-qter and 20q11-qter and deletion of most of chromosome 6 (6p23-qter) were detected by CGH. Because of uncertainty about some of the indicated changes, including a deletion of 1p35-pter, the CGH findings were investigated more closely by chromosome painting, leading to a revision of the karyotype: 45,XX,del(1)(p35),−6,dup(8)(pter→qter::qter→q24),der(12) t(6;12)(p23;p13),der(14)t(5;14)(q22;q32.3),der(17)t(8;17;20)(17pter→17q25::8qter→8q23::8q24→8qter::8q24→8qter::8q23→8q24.1::20q11→20qter). Some karyotypic changes were confirmed by CGH; others had to be revised; and, in the 1p35 region, classical cytogenetics seems superior to CGH. However, CGH revealed a karyotypically unsuspected dup(20q) that might be of special relevance to breast tumor initiation or progression. Our study confirms that CGH is supplementary to current technologies, e.g., karyotyping and Southern analysis, but cannot replace them. In addition, our cell line turned out to be an excellent model for comparison among the different methods. The results imply that future cytogenetic analyses of complex karyotypes should be based on a combination of karyotyping, CGH, and FISH. Genes Chromosom. Cancer 20:30–37, 1997. © 1997 Wiley-Liss, Inc.     

Psychometric evaluation of an item bank for computerized adaptive testing of the EORTC QLQ-C30 cognitive functioning dimension in cancer patients

Background

The European Organisation of Research and Treatment of Cancer (EORTC) Quality of Life Group is developing computerized adaptive testing (CAT) versions of all EORTC Quality of Life Questionnaire (QLQ-C30) scales with the aim to enhance measurement precision. Here we present the results on the field-testing and psychometric evaluation of the item bank for cognitive functioning (CF).

Methods

In previous phases (I–III), 44 candidate items were developed measuring CF in cancer patients. In phase IV, these items were psychometrically evaluated in a large sample of international cancer patients. This evaluation included an assessment of dimensionality, fit to the item response theory (IRT) model, differential item functioning (DIF), and measurement properties.

Results

A total of 1030 cancer patients completed the 44 candidate items on CF. Of these, 34 items could be included in a unidimensional IRT model, showing an acceptable fit. Although several items showed DIF, these had a negligible impact on CF estimation. Measurement precision of the item bank was much higher than the two original QLQ-C30 CF items alone, across the whole continuum. Moreover, CAT measurement may on average reduce study sample sizes with about 35–40% compared to the original QLQ-C30 CF scale, without loss of power.

Conclusion

A CF item bank for CAT measurement consisting of 34 items was established, applicable to various cancer patients across countries. This CAT measurement system will facilitate precise and efficient assessment of HRQOL of cancer patients, without loss of comparability of results.

     

Dietary Patterns and Birth Weight—a Review

Being born with low birth weight (LBW) is recognized as a disadvantage due to risk of early growth retardation, fast catch up growth, infectious disease, developmental delay, and death during infancy and childhood, as well as development of obesity and non-communicable diseases (NCDs) later in life. LBW is an indicator of fetal response to a limiting intrauterine environment, which may imply developmental changes in organs and tissue. Numerous studies have explored the effect of maternal intake of various nutrients and specific food items on birth weight (BW). Taking into account that people have diets consisting of many different food items, extraction of dietary patterns has emerged as a common way to describe diets and explore the effects on health outcomes. The present article aims to review studies investigating the associations between dietary patterns derived from a posteriori analysis and BW, or being small for gestational age (SGA). A PubMed search was conducted with the Mesh terms “pregnancy” OR “fetal growth retardation” OR “fetal development” OR “infant, small for gestational age” OR “birth weight” OR “infant, birth weight, low” AND “diet” OR “food habits”. Final number of articles included was seven, all which assessed diet by use of food frequency questionnaire (FFQ). Five studies explored dietary patterns using principal component analyses (PCA), while one study used cluster analyses and one study logistic regression. The studies reported between one and seven dietary patterns. Those patterns positively associated with BW were labeled “nutrient dense”, “protein rich”, “health conscious”, and “Mediterranean”. Those negatively associated with BW were labeled “Western”, “processed”, “vegetarian”, “transitional”, and “wheat products”. The dietary patterns “Western” and “wheat products” were also associated with higher risk of SGA babies, whereas a “traditional” pattern in New Zealand was inversely associated with having a SGA baby. The dietary patterns associated with higher BW or lower risk of having babies born SGA were named differently, but had similar characteristics across studies, most importantly high intakes of fruits, vegetables and dairy foods. Dietary patterns associated with lower BW or higher risk for giving birth to a SGA baby were characterized by high intakes of processed and high fat meat products, sugar, confectionaries, sweets, soft drinks, and unspecified or refined grains. All studies in this review were performed in high-income countries. More research is warranted to explore such associations in low and middle income countries, where underweight babies are a major health challenge many places. Furthermore, results from studies on associations between diet and BW need to be translated into practical advice for pregnant women, especially women at high risk of giving birth to babies with LBW.     

How do we sell the hygiene message? With dollars,dong or excreta?

In North and Central Vietnam it is common among farmers to use excreta from the family double vault composting latrine (DVC) as fertilizer in the fields. The official Vietnamese health guidelines stipulate a six-month period of composting before applying excreta to two of their three annual crops. However, farmers in this region cannot afford to follow these guidelines and this paper presents the reasons why.