Lipopolysaccharide-induced suppression of graft-versus-host reactivity in mice

Reconstitution of lethally irradiated mice with spleen cells from donors that had been treated with lipopolysaccharide (LPS) intravenously and allogeneic spleen cells subcutaneously leads to a suppressed anti-host delayed-type hypersensitivity (DTH). Either donor injection alone proved to be ineffective. The state of suppression appeared to be antigen-specific, but, depending on the experimental conditions, also anti-host DTH to third-party alloantigens could be suppressed. The suppression was mediated by a population of Thy-1- suppressor cells that could also be induced in athymic nude mice. The suppressor cells specifically adhered to anti-kappa-coated plastic plates, but were not adsorbed by passage through a Sephadex G-10 column. Thus, it appears that the combined donor treatment with LPS and allogeneic spleen cells induces a population of B cells that can suppress anti-host immune reactivity.     

The force-velocity relationship of arm flexion in untrained males and females and arm-trained athletes

Summary The force-velocity curve (FVC) of arm flexion was established in 123 untrained males and 110 untrained females aged from 15 to 36 years, and 48 arm-trained athletes competing in different sport disciplines. The FVC was described by Hill's equation and defined by the parameters: maximal static moment (M₀), maximal angular velocity (₀), maximal power (P₀) and the concavity of the FVC (H). Within the given age range the level of the curve parameters of both untrained men and women was independent of age.On average, H was the same in all three groups. As compared to M₀ of the untrained males, M₀ of the athletes was 33% higher and M₀ of the females was 38% lower; with regard to P₀ these differences were +30% and –43% respectively. ₀ was the same for trained and untrained males, wherease ₀ of the women was 10% lower than ₀ of the men.     

Interaction of biodegradable β-whitlockite ceramics with bone tissue: An in vivo study

The biodegradation of different porous β-whitlockite materials are studied by in vivo experiments, radiographie follow-ups and light microscopy observations. The materials were implanted in rabbit tibiae for 16 mnth. Micropores play an important role in the biodegradation rate. The resorbing materials evoke an inflammation with plasma cells. The resorption starts in the medulla, and the phagocytosed particles are removed to the lymph nodes. Normal bone function can be restored after all the implant material is resulted.     

Causes of Stability of Aggression from Early Childhood to Adolescence: A Longitudinal Genetic Analysis in Dutch Twins

This study investigated the contribution of genetic and environmental influences on the stability of aggressive behavior from early childhood to adolescence. Two developmental models, the simplex model and the common factor model, were tested to study the underlying processes of stability and change. Measures of aggressive behavior (AGG) were obtained from maternal CBCL data as part of a large ongoing longitudinal study of the Netherlands Twin Registers (NTR) and included data from 6488 three-year-old twin pairs, 5475 seven-year-old twin pairs, 2983 ten-year-old twin pairs, and 1509 twelve-year-old twin pairs. AGG showed moderate to high stability during childhood. The stability coefficients ranged from 0.41 to 0.77 across varying intervals. Averaged across boys and girls, genetic factors accounted for approximately 65% of the total stability. Longitudinal genetic analysis indicated a simplex model for genetic effects, which suggests a dynamic development process consisting of transmission of existing genetic effects interacting with new genetic influences. This is especially true at age 7, when the influence of new genetic factors was large. Shared environmental factors accounted for approximately 25% of phenotypic stability, and it seemed that a stable set of the same shared environmental factors underlay the development of AGG. Nonshared environmental factors, when important, are age specific. Sex-specific differences for stability were identified. For boys, genetic influences were greater, whereas for girls shared environmental factors were more important. These data support the idea that both genetic and environmental influences play a role in the stability of AGG from age 3 to 12.     

Astrocytes and intracerebral immune responses

The astrocyte is the most abundant cell within the central nervous system (CNS). This cell subserves a multiplicity of important functions that contribute to the process of neural development as well as to the integrity of normal brain function. Adding to the already exhaustive list of capabilities, the astrocyte has now been demonstrated to function as an intracerebral antigen presenting cell. These findings are serving to revise our view of the brain as an immunoprivileged site and perhaps will shed some light on the pathogenetic mechanisms involved in a number of CNS disorders of immune dysregulation. In this review we provide some perspective on the regulatory mechanisms that influence astrocyte immune functions. Specifically, we address the role played by the major histocompatibility complex (MHC) antigens as well as adhesion molecules in the initiation of brain immune responses.     

Hyperimmunized patients do not need to wait for an HLA identical donor

Hyperimmunized patients tend to accumulate on renal transplant waiting lists because their high level of sensitization leads to positive crossmatches with almost all potential organ donors. The origins of sensitization and the different efforts made to find cross-match negative donors for these patients are discussed. Special emphasis is given to a local strategy based on the determination of HLA-A and -B mismatches, against which the patient did not form allo-antibodies, the so-called acceptable mismatches. Kidney donor selection is based on compatibility with the patient's own HLA-antigens in combination with the acceptable HLA-A and -B antigens, and can be operated from a central organ-sharing office. The acceptable HLA mismatches are often identical with or include the non-inherited HLA class I antigens of the mother (non-inherited maternal antigens: NIMA).     

A patient with an interstitial deletion of the short arm of chromosome 6

The clinical history and subsequent progress of a child with an interstitial deletion in the short arm of chromosome 6 is described. This abnormality coupled with a reduced Hageman factor (Factor XII) led to an earlier publication which suggested that this gene was localized to the breakpoint region involved. A review of similar phenotypes from the literature is presented.     

Comparison of four genotyping assays for epidemiological study of methicillin-resistantStaphylococcus aureus

Twenty-six methicillin-resistantStaphylococcus aureus strains were genetically differentiated by interrepeat PCR and the results compared with those of ribotyping, pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA analysis obtained in a previous study for the same strains. The comparison showed that the PCR-mediated assays were as discriminatory as PFGE, whereas ribotyping was the least powerful genotyping method. Due to the ease of performance, PCR fingerprinting may become the method of choice for establishing clonal relationships amongStaphylococcus aureus isolates.