SLE and malaria: another look at an old idea

An alternative view of the relationship between autoimmune disease and malaria is provided in the following article by Geoff Butcher and Ian Clark. Here they reassess the evidence that favours an earlier suggestion that where parasitic infections are common, autoimmune disease is rare. They suggest that malaria may exert a protective effect against the autoimmune nephritis in systemic lupus erythematosus (SLE).     

HIV-1 attachment: another look

HIV-1 attachment to host cells is generally considered to take place via high-affinity binding between CD4 and gp120. However, the binding of virion-associated gp120 to cellular CD4 is often weak, and most cell types that are permissive for HIV-1 infection express little CD4. Thus, other interactions between the virion and the cell surface could dominate the attachment process.     

When second best is good enough: another probabilistic look at saturation mutagenesis

We developed new criteria for determining the library size in a saturation mutagenesis experiment. When the number of all possible distinct variants is large, any of the top-performing variants (e.g., any of the top three) is likely to meet the design requirements, so the probability that the library contains at least one of them is a sensible criterion for determining the library size. By using a criterion of this type, one may significantly reduce the library size and thus save costs and labor while minimally compromising the quality of the best variant discovered. We present the probabilistic tools underlying these criteria and use them to compare the efficiencies of four randomization schemes: NNN, which uses all 64 codons; NNB, which uses 48 codons; NNK, which uses 32 codons; and MAX, which assigns equal probabilities to each of the 20 amino acids. MAX was found to be the most efficient randomization scheme and NNN the least efficient. TopLib, a computer program for carrying out the related calculations, is available through a user-friendly Web server.     

Gregariousness versus solitude: another look at parasite faunal richness in Canadian freshwater fishes

Summary The expectation of the ideal free distribution is a functional response in which intake is constant in all sites and, if interference is low, an aggregative response in which all individuals cluster in the high prey density sites. Incorporating individual differences in competitive ability results in a functional response in which intake increases with prey density and an aggregative response in which individuals are more evenly distributed.     

Risky sexual behaviour among unmarried young people in Cameroon: another look at family environment

Most studies of the association between family structure and risky sexual behaviour among adolescents and young adults have employed a risk perspective which assumes that, compared with other types, two-parent families are protective. Drawing from a positive-oriented approach in this study, it is hypothesized that within each family type some influential factors may mitigate such anticipated deleterious effects of non-intact families and decrease sexual risk-taking. The paper examines specifically the effects of risk and protective factors with an emphasis on family processes associated with resilience, using data from a pooled sample of 1025 females and males aged 12-24 years from Bandjoun (West Cameroon). Findings show that the quality of parent/guardian-youth relationships significantly decreases the odds of risky sexual behaviour by 36%, 65% and 50% in neither-, one- and two-parent families, respectively. For two-parent families only, parental control acts as a significant protective factor; it decreased by 41% the odds of risky sexual behaviour. Programmatically, protective family factors such as parent/guardian-youth interactions need to be promoted to improve the efficiency of reproductive health and HIV interventions in sub-Saharan Africa.     

The A system of horse erythrocyte alloantigens: a new allele and another look at factor Ae

Family data are presented for a new allele (Aabdg) in the A system of horse erythrocyte alloantigens which includes factors Aa and Ab traditionally thought to be products of allelic genes. Evidence for incorrect assignment of the codominant factor Ae in the presence of Ab and Ac and the absence of Aa is discussed.     

Another look at cryoprostatectomy

The early 1960s witnessed a marked advancement in cryogenic research and its clinical application to surgery. Cooper's development of a closed controllable method for destruction of tissue by cryosurgery was at the forefront. In 1964, Gonder et al. (3) modified this apparatus and popularized its use in the treatment of the common problem of the obstructing prostate gland. However, this potential panacea soon presented the urologists with unexpected serious complicaions. Prolonged sloughing of the necrotized prostate, accidental freezing of rectum, bladder, external urethral sphincter occurred which were unacceptable and rarely encountered with conventional methods of prostatectomy. At this point in time, most urologists in the United States abandoned this procedure. However, others persisted and modified this technique with more precise methods of control monitoring and utilized a small resection of thawing prostate at the time of cryoprostatectomy. During this transition phase, the indications were justifiably narrowed to (i) poor-risk patients, (ii) those with hematological problems, (iii) treatment of large inoperable prostate carcinomas. Our experience with the last 100 cases of combined cryotransurethral prostatectomy encourages another look at this procedure. The utilization of this method, however, must be restricted to a select group of patients and should be carried out by only those urologists properly trained in this surgical modality.     

Taking another look with fluorescence microscopy: Image processing techniques in Langmuir monolayers for the twenty-first century

Fluorescence microscopy has become a powerful and standard complementary technique in the study of amphiphilic films at the air-water interface. For nearly three decades the coupling of traditional thermodynamic measurements with direct visualization has provided a better understanding of self-assembled Langmuir monolayers and their application in the study of the physical properties of membranes and interfaces. As an introduction we provide a brief overview of this established technique and demonstrate its continued utility in the recent observation of novel phase behavior in monolayers of 25-hydroxycholesterol (25-OH) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). We then focus our review on new analysis techniques which take advantage of the ability to store, process, and analyze large sets of images. We pay particular attention to efforts measuring the line tension between coexisting two dimensional fluid phases in the Langmuir monolayer. Using non-perturbative methods, we can measure fundamental mechanical properties of these two dimensional systems. Finally, we highlight the use of Model Convolution Microscopy as a new tool to provide insight on the experimental limits in these studies.     

A first look at biosensors

This is a very elementary guide to biosensors, outlining the principles of operation of some optoelectronic and current measuring biosensors. Factors which can influence successful translation to the marketplace are addressed.