Rebound effect of the allogenic T-cell response to donor and third-party lymphocytes after cyclosporine withdrawal in renal transplant recipients

Mixed lymphocyte reaction (MLR) assays were performed serially over 24 months in 19 first cadaver renal transplant recipients. Immunosuppression consisted of cyclosporine, methylprednisolone and azathioprine. Cyclosporine was withdrawn at 6 months postoperatively. The MLR reactivity gradually decreased over the first 3 months following transplantation. However, there was a significant increase in MLR reactivity at 12 months postoperatively after the cyclosporine withdrawal. This rebound effect in MLR reactivity following cyclosporine withdrawal could account for the increased incidence of acute rejection episodes.     

Evidence for chelatable zinc in the extracellular space of the hippocampus, but little evidence for synaptic release of Zn

Zinc colocalizes with glutamate in the synaptic vesicles of certain glutamatergic vesicles in the mammalian brain. Here, I introduce a method for detecting Zn in the extracellular space of brain slices and another method for detecting the passage of Zn out of the slice. In both cases, the fluorimetric Zn probe FluoZin-3 is used in conjunction with a slow Zn chelator, Ca-EDTA, to reduce background fluorescence. In addition, a new Zn chelator, ethylenediiminodi-2-pentanedioic acid, with little affinity for Ca or Mg is introduced. These tools are then used to show that little Zn (approximately 2 nm) is released during the course of synaptic transmission into the extracellular space. However, when hippocampal slices are subjected to a high potassium stimulus (50 mM) combined with an increase in osmolarity, Zn is externalized in the Timm's-stained areas (approximately 6 nm). This stimulus also leads to even greater Zn elevations in area CA1 that is only weakly stained by the Timm's method. Nevertheless, even under these conditions, little if any Zn makes its way out of the slices. I present evidence for a layer of Zn in the extracellular space that maps onto the Timm's stained region of the hippocampus. This Zn veneer appears to be loosely associated with molecules in the extracellular space and may be the raison d'être for vesicular Zn.     

The incidence of sexually acquired reactive arthritis: a systematic literature review

Reactive arthritis (ReA) is an inflammatory spondyloarthritis occurring after infection at a distant site. Chlamydia trachomatis is proposed to be the most common cause of ReA, yet the incidence of sexually acquired ReA (SARA) has not been well established. We therefore carried out a systematic literature review to collate and critically evaluate the published evidence regarding the incidence of SARA. MEDLINE and EMBASE databases were searched using free-text and MeSH terms relating to infection and ReA. The title and abstract of articles returned were screened independently by two reviewers and potentially relevant articles assessed in full. Data was extracted from relevant articles and a risk of bias assessment carried out using a validated tool. Heterogeneity of study methodology and results precluded meta-analysis. The search yielded a total of 11,680 articles, and a further 17 were identified from review articles. After screening, 55 papers were assessed in full, from which 3 met the relevant inclusion criteria for the review. The studies reported an incidence of SARA of 3.0–8.1 % and were found to be of low to moderate quality. More studies are required to address the lack of data regarding the incidence of SARA. Specific and sensitive classification criteria must be developed in order for consistent classification and valid conclusions to be drawn. In clinical practice, it is recommended clinicians discuss the possibility of ReA developing at the time of STI diagnosis and to encourage patients to return if they experience any relevant symptoms.     

The BCR gene recombines preferentially with Alu elements in complex BCR- ABL translocations of chronic myeloid leukaemia

Chronic myeloid leukaemia (CML) develops when two genes, BCR on chromosome 22 and ABL on chromosome 9, recombine to form a hybrid BCR- ABL gene with leukaemogenic properties. The mechanism which underlies this recombination is unknown, but additional chromosome sites may be involved to form complex BCR-ABL rearrangements. The majority of breakpoints in BCR occur within a 5 kb major breakpoint cluster region, M-Bcr. Here, we show that the 3' part of M-Bcr recombined within, or immediately adjacent to, Alu elements at the additional sites in all five complex BCR-ABL rearrangements that have been examined so far. This is a new finding which suggests that Alu sequences have an affinity for the BCR-ABL recombination process in complex rearrangements, and provides additional evidence for the association of these elements with somatic rearrangements which cause human leukaemia. We further show that sequence motifs similar to IgH switch pentamers and consensus binding sites of the lymphoid-associated Translin protein are present on one or more participating strands at 3'M-Bcr recombination sites. Motifs similar to Translin-binding sites were also identified within the Alu consensus. Expressed sequences mapped close to the breakpoint sites on other chromosomes in three of the five cases examined.      

A high frequency African coding polymorphism in the N-terminal domain of ICAM-1 predisposing to cerebral malaria in Kenya

The malarial parasite Plasmodium falciparum has acted as a potent selective force on the human genome. The particular virulence of this organism is thought to be due to the adherence of parasitised red blood cells to small vessel endothelium through several receptors, including CD36, thrombospondin and intercellular adhesion molecule 1 (ICAM-1, CD54), and parasite isolates differ in their ability to bind to each. Immunohistochemical studies have implicated ICAM-1 as of potential importance in the pathogenesis of cerebral malaria, leading us to reason that if any single receptor were involved in the development of cerebral malaria, then in view of the high mortality of that complication, natural selection should have produced variants with reduced binding capacity. We therefore sequenced the N-terminal domain of ICAM-1 from a number of Africans and discovered a single mutation present at high frequency. Genotypes at this locus from samples from a case-control study indicated an association of the polymorphism with the severity of clinical malaria such that individuals homozygous for the mutation have increased susceptibility to cerebral malaria with a relative risk of two. These counterintuitive results have implications for the mechanism of malaria pathogenesis, resistance to other infectious agents and transplantation immunology.      

Morphology of intestinal allograft rejection and the inadequacy of mucosal biopsy in its recognition

Small intestinal segmental autografts and allografts in dogs were examined histologically to assess changes associated with the surgical technique, the effect of different luminal perfusates and for evidence of rejection. Some animals were immunosuppressed with Cyclosporin A. Specimens for examination were obtained by biopsy at regular intervals after transplantation, at death or when killed. Typical vascular changes of rejection were identified only within some allografts and in others the cause of graft failure remains conjectural. When there was rejection characteristic lesions were confined to the submucosa and muscle coats while changes in the mucosa were similar to those in the autografts. These mucosal features were affected by the nature of the perfusate and often appeared transiently after grafting. Mucosal biopsy as a way of monitoring intestinal allograft rejection neither reveals a sequential pattern of changes, nor provides a reliable method of recognition of the reaction. In contrast full thickness biopsies of the intestinal wall do appear to fulfil both of these requirements.     

Variation in the matrix metalloproteinase-3, -7, -12 and -13 genes is associated with functional status in rheumatoid arthritis

As matrix metalloproteinases (MMPs) play an important role in rheumatoid arthritis, we investigated whether variation in MMP genes was associated with functional disability in rheumatoid arthritis patients. A cohort of patients with seropositive rheumatoid arthritis were recruited and genotyped for the MMP1-1607 1G > 2G, MMP3-1612 5A > 6A, MMP7-153C > T, MMP7-181G > A, MMP12-82A > G and MMP13-77A > G polymorphisms. Genotypes were then analysed in relation to functional disability assessed by Steinbrocker index and Health Assessment Questionnaire (HAQ) score. We detected an association between the MMP13-77 A > G polymorphism and Steinbrocker index, with patients of the A/A genotype having higher score than patients of the A/G or G/G genotype (P = 0.005), and the association remained significant after adjusting for age, sex, erythrocyte sedimentation rate, presence of erosive disease, Ritchie score, prednisolone therapy and years of diagnosis (P = 0.003). We also observed a relationship of Steinbrocker index with the MMP3-1612 5A > 6A, MMP7-181 A > G and MMP12-82A > G polymorphisms (P = 0.082, P = 0.037 and P = 0.045). No association was detected between the MMP1-1607 1G > 2G and MMP7-153C > T polymorphisms and either Steinbrocker index or HAQ score. These results suggest that MMP3, MMP7, MMP12 and MMP13 genotypes may play a role in determining functional status of rheumatoid arthritis.     

Comparative efficacy of two microdoses of a potentized homoeopathic drug, Cadmium Sulphoricum, in reducing genotoxic effects produced by cadmium chloride in mice: a time course study

Background  

Cadmium poisoning in the environment has assumed an alarming problem in recent years. Effective antimutagenic agents which can reverse or combat cadmium induced genotoxicity in mice have not yet been reported. Therefore, in the present study, following the homeopathic principle of "like cures like", we tested the efficacy of two potencies of a homeopathic drug, Cadmium Sulphoricum (Cad Sulph), in reducing the genotoxic effects of Cadmium chloride in mice.