Detection of heat-stable antigens of Campylobacter jejuni and C. coli by direct agglutination and passive hemagglutination

The two serotyping schemes for the detection of heat-stable antigens of Campylobacter jejuni and Campylobacter coli use the same strains for antiserum production but differ in the detection systems used for identifying agglutination. The Penner method uses passive hemagglutination (PHA) while the Laboratory of Enteric Pathogens method uses the same antisera but in a whole-bacterial-cell direct agglutination (DA) protocol. C. jejuni produces a polysaccharide capsule, which is antigenic, and is the main component detected by the PHA method. The DA method will detect both capsule antigens and lipopolysaccharide (LPS) or lipooligosaccharide (LOS) surface antigens. Comparison of both methods by using a selection of isolates from human infection has shown a range of variation in agglutination specificity, reflecting the differences in antigens detected by the two methods. While 27.4% of the 416 C. jejuni isolates reacted with the antisera raised against the same type strains by either method, the majority showed a range of more complex relationships. None of the 37 C. coli isolates reacted with the same antiserum by both methods. Together the two schemes gave a total of 102 distinct combined serogroups for C. jejuni and 16 for C. coli. Thus, while some clonally related isolates share the same capsule and LOS or LPS antigens, other strains appear to have a common capsule antigen but differ in their LPS or LOS structures or vice versa.     

Comparison of Frontal EMG Biofeedback and Several Types of Relaxation Instructions in Reducing Multiple Indices of Arousal

During the training phase, 96 subjects were given one of four types of relaxation instructions (single instructions, repeated instructions, relaxation training, no instructions) and in addition either did or did not receive frontal EMG biofeedback training. Results indicated that each of the instructions and biofeedback procedures were equally effective in reducing frontal EMG, but that none of these procedures had any effect on subjective anxiety or autonomic indices of arousal (pulse rate, skin temperature, and finger pulse volume). During the generalization/stress phase, subjects were threatened with electric shock and were told to apply the relaxation techniques they learned during the training phase even though no additional instructions and/ or biofeedback training would be provided. To assess the effectiveness of the shock manipulation, a no-threat control group was included. Results indicated that: a) the shock manipulation was effective in increasing arousal, b) previous instructions and/or biofeedback were equally effective in reducing frontal EMG levels, but that c) only relaxation training was consistently effective in reducing subjective and autonomic indices of arousal. These findings: a) suggest that in stressful situations, relaxation training may be more effective than either EMG biofeedback or simple relaxation instructions in producing a general relaxation effect as opposed to a specific EMG effect; and b) indicate the importance of assessing the effectiveness of relaxation procedures during stressful situations during which subjects’ levels of arousal are elevated above resting baseline levels.     

Bone “mass” and the “mechanostat”: A proposal

The observed fit of bone mass to a healthy animal's typical mechanical usage indicates some mechanism or mechanisms monitor that usage and control the three longitudinal growth, bone modeling, and BMU-based remodeling activities that directly determine bone mass. That mechanism could be named a mechanostat. Accumulated evidence suggests it includes the bone itself, plus mechanisms that transform its mechanical usage into appropriate signals, plus other mechanisms that detect those signals and then direct the above three biologic activities. In vivo studies have shown that bone strains in or above the 1500–3000 microstrain range cause bone modelling to increase cortical bone mass, while strains below the 100–300 microstrain range release BMU-based remodeling which then removes existing cortical-endosteal and trabecular bone. That arrangement provides a dual system in which bone modeling would adapt bone mass to gross overloading, while BMU-based remodeling would adapt bone mass to gross underloading, and the above strain ranges would be the approximate “setpoints” of those responses. The anatomical distribution of those mechanical usage effects are well known. If circulating agents or disease changed the effective setpoints of those responses their bone mass effects should copy the anatomical distribution of the mechanical usage effects. That seems to be the case for many agents and diseases, and several examples are discussed, including postmenopausal osteoporosis, fluoride effects, bone loss in orbit, and osteogenesis imperfecta. The mechanostat proposal is a seminal idea which fits diverse evidence but it requires critique and experimental study.     

Family Belongingness Attenuates Entrapment and Buffers Its Association with Suicidal Ideation in a Sample of Dutch Sexual Minority Emerging Adults

Sexual minority emerging adults are more likely to engage in suicidal ideation than their heterosexual counterparts. Experiences of homophobic violence are associated with suicidal ideation. Yet, the specific mechanisms linking homophobic violence to suicidal ideation remain unclear. Entrapment and social belongingness were tested to determine their relevance for understanding the link between homophobic violence and suicidal ideation. A sample of sexual minority Dutch emerging adults (N?=?675; ages 18–29, M?=?21.93 years, SD?=?3.20) were recruited through online platforms and flyers. Homophobic violence was expected to be positively associated with suicidal ideation and entrapment. The association between homophobic violence and suicidal ideation was expected to be indirectly linked through entrapment. We explored whether various sources of social belongingness moderated the path between entrapment and suicidal ideation and whether those sources of social belongingness moderated the indirect effect of homophobic violence on suicidal ideation through entrapment. Results showed that homophobic violence and entrapment were positively associated with suicidal ideation and that family belongingness was negatively associated with suicidal ideation. Homophobic violence and suicidal ideation were not indirectly linked through entrapment. The interaction effect between entrapment and family belongingness was significant, suggesting that, on average, the effect of entrapment on suicidal ideation decreased when family belongingness was high. These results suggest that family belongingness may reduce the association between entrapment and suicidal ideation while adjusting for homophonic violence. Reducing entrapment and improving family belongingness may be useful targets for programs aimed at preventing suicidal ideation among sexual minority emerging adults.

     

Persistent Subcutaneous Nodules in Children Hyposensitized with Aluminium-Containing Allergen Extracts

A follow-up study of 202 children who had received hyposensitization with aluminium-containing allergens showed that 1-3 years after cessation of hyposensitization 13 children still had severely pruiginous treatment-resistant subcutaneous nodules in their forearms. Because of their long persistence the nodules of six children were studied in detail. Histologically, the nodules showed infiltration with lymphocytes (forming germinal centres), macrophages, plasma cells, mast cells and a few eosinophils. In five patients aluminium crystals were found scattered between the cells and, in addition, the phagosomes of the macrophages contained aluminium. Patch tests for aluminium were positive in four of the six patients. It is concluded that persisting nodules during hyposensitization with aluminium-containing allergens may indicate development of aluminium hypersensitivity, and if this is confirmed hyposensitization should be discontinued.     

Suggested fundamental concepts in skeletal physiology

Conclusion By 1990, the work and thought of legions led to a new paradigm of skeletal biology [1, 2, 8, 15–27]. It is not the product of one man or group, even though one group wrote more about it than others. Its strength and potential usefulness lie more in its basic concepts, the common denominators or connections in diverse facts, than in the facts themselves. It melds ideas and information from many branches of skeletal science so it has multidisciplinary roots and one could say its concepts lie on many shelves (including, in part anatomic, biochemical, biomechanical, cell biologic, clinical, and pathologic ones). It still evolves; it is fluid. This article offers a brief look at some concepts on its vital biomechanical shelf [28]. They can suggest the skeleton's mechanical usage story is more deeply involved in supposedly medical skeletal affections than anyone suspected a decade or more ago.     

IMPORTANCE OF DONOR SELECTION IN RENAL TRANSPLANTATION

Renal transplantation has become a treatment of choice for patients with end stage renal disease. A successful transplant is the result of a combination of several factors acting synergistically, such as the degree of HLA compatibility between donor and the recipient, pretransplant blood transfusions, the recipient''s state of immunoreactivity and sensitization, immunosuppressive therapy given in post operative period etc. Donor selection appears to be the most critical factor for the long term success of the organ graft. In this brief review, some of the important parameters of donor selection in renal transplantation are highlighted.KEY WORDS: Histocompatibility (HLA) matching, Cross match, Sensitization     

The cerebellum's role in reading: a functional MR imaging study

BACKGROUND AND PURPOSE: Long considered to have a role limited largely to motor-related functions, the cerebellum has recently been implicated as being involved in both perceptual and cognitive processes. Our purpose was to determine whether cerebellar activation occurs during cognitive tasks that differentially engage the component processes of word identification in reading. METHODS: Forty-two neurologically normal adults underwent functional MR imaging of the cerebellum with a gradient-echo echo-planar technique while performing tasks designed to study the cognitive processing used in reading. A standard levels-of-processing paradigm was used. Participants were asked to determine whether pairs of words were written in the same case (orthographic processing), whether pairs of words and non-words rhymed with each other, respectively (phonologic assembly), and whether pairs of words belonged to the same category (semantic processing). Composite maps were generated from a general linear model based on a randomization of statistical parametric maps. RESULTS: During phonologic assembly, cerebellar activation was observed in the middle and posterior aspects of the posterior superior fissure and adjacent simple lobule and semilunar lobule bilaterally and in posterior aspects of the simple lobule, superior semilunar lobule, and inferior semilunar lobule bilaterally. Semantic processing, however, resulted in activation in the deep nuclear region on the right and in the inferior vermis, in addition to posterior areas active in phonologic assembly, including the simple, superior semilunar, and inferior semilunar lobules. CONCLUSION: The cerebellum is engaged during reading and differentially activates in response to phonologic and semantic tasks. These results indicate that the cerebellum contributes to the cognitive processes integral to reading.