Specificities in human cell-mediated cytotoxicity.

Specificity of natural cell-mediated cytotoxicity was investigated through selective reactions detected by direct cell-mediated cytotoxicity and by inhibition of cytotoxicity through competition. Assuming that target cells reacting alike in direct cytotoxicity shared common antigens, we classified 10 target cells into three groups by target antigens: TA (target antigen) 1, 2, and 3. Partial confirmation of the three groups was achieved in the cross-competition assay. The distinction of TA 1 as a group was clear but some cross-reactivity existed between TA 2 and TA 3 cells.     

Presensitization and kidney transplant failures

Over 1000 kidney transplant patients were tested for cytotoxic antibodies before transplantation.     

Preventing HIV transmission to children: quality of counselling of mothers in South Africa

AIM: To assess the quality of counselling provided to mothers through the programme to prevent mother-to-child transmission (PMTCT) of HIV in South Africa. METHODS: Structured observations of consultations and exit interviews with 60 mothers attending clinics at three purposively selected PMTCT sites across South Africa were conducted. RESULTS: Twenty-two counsellors were observed. The general quality of communication skills was very good, and 73% of HIV-negative mothers were informed of the advantages of exclusive breastfeeding (EBF). However, only one of 34 HIV-positive mothers was informed about the possible side effects of nevirapine, and none was told what to do when it occurred. Only two HIV-positive mothers were asked about essential conditions for safe formula feeding before a decision about an infant feeding option was made. None of the 12 mothers choosing to breastfeed was shown how to position the baby correctly on the breast or asked whether they thought EBF was feasible. Fewer than a quarter of mothers expressed confidence in performing the actions required, and 85% could not define the term EBF. CONCLUSION: The poor quality of counselling in the PMTCT programme will reduce the effectiveness of these programmes. As they are being scaled up, there needs to be far more attention paid towards the counselling of mothers, especially with regards to optimal infant feeding.     

Do older adults use the Internet for information on heart attacks? Results from a survey of seniors in King County, Washington

BACKGROUND: Early treatment can reduce mortality from heart attacks. However, patient delay, especially among the elderly, has slowed progress in this area. One of the reasons for delay may be because of a lack of knowledge about symptoms of acute myocardial infarction (AMI) and treatment benefits. The Internet is a new and promising source of heart health information, but we know little about how elderly people use this medium. METHODS: This study investigates the demographic and psychosocial variables that are related to Internet access, health information seeking, and information seeking about heart attacks from the Internet among seniors. We interviewed seniors (N = 323) aged more than 65 years and asked them questions about Internet access, health information seeking, and information seeking on heart attacks, as well as demographic information, risk perceptions for AMI, and personal experience with AMI. RESULTS: The results showed that several demographic variables were related to access to the Internet. Only 7% of the seniors who reported access to the Internet had sought information on heart attacks from the Internet. Age, history of AMI, and family history of AMI were significant predictors of information seeking on heart attacks. This suggests that to date only a very small, high-risk group of seniors actually seeks information on heart attack emergencies from the Internet.     

Impaction allografting for femoral component revision: clinical update

The technique of cancellous impaction allografting with cement aims to reconstitute a bone-deficient proximal femur while also gaining stable fixation of the femoral prosthesis. Some reports of this technique imply it is a system, requiring not just an exacting surgical method, but also a particular implant design, the polished, double-tapered stem. Other series consider it a surgical technique, and have varied the femoral component design, the method of graft delivery, and other elements of the procedure. Our review evaluates the current literature, with the goal of beginning to ascertain whether published results suggest impaction grafting must be considered a system, requiring a particular stem design, or simply another means to achieve femoral reconstruction in the revision setting. The conclusive answer will require randomized, controlled clinical trials to evaluate particular elements of the procedure, and these studies have yet to be done. However, investigators have shown similarly good short-term to intermediate-term results with various femoral stems at numerous centers. Currently, femoral impaction allografting, whether as a system using particular implant designs or as a surgical technique, is an accepted alternative for revision of a failed femoral component, particularly when bone-stock deficiency is present.     

Cone pigment polymorphism in New World monkeys: are all pigments created equal?

Most platyrrhine monkeys have a triallelic M/L opsin gene polymorphism that underlies significant individual variations in color vision. A survey of the frequencies of these polymorphic genes suggests that the three alleles occur with equal frequency among squirrel monkeys (subfamily Cebinae), but are not equally frequent in a number of species from the subfamily Callitrichinae. This departure from equal frequency in the Callitrichids should slightly increase the ratio of dichromats to trichromats in the population and significantly alter the relative representation of the three possible dichromatic and trichromatic phenotypes. A particular feature of the inequality is that it leads to a relative increase in the number of trichromats whose M/L pigments have the largest possible spectral separation. To assess whether these trichromatic phenotypes are equally well equipped to make relevant visual discriminations, psychophysical experiments were run on human observers. A technique involving the functional substitution of photopigments was used to simulate the discrimination between fruits among a background of leaves. The goal of the simulation was to reproduce in the cones of human observers excitations equivalent to those produced in monkey cones as the animals view fruit. Three different viewing conditions were examined involving variations in the relative luminances of fruit and leaves and the spectrum of the illuminant. In all cases, performance was best for simulated trichromacies including M/L pigments with the largest spectral separation. Thus, the inequality of opsin gene frequency in Callitrichid monkeys may reflect adaptive pressures.