Resolution of complex feline leukocyte antigen DRB loci by reference strand-mediated conformational analysis (RSCA)

The DRB genes of the domestic cat are highly polymorphic. Studies based on clonal sequence analysis have suggested the existence of two distinct loci within individual animals and good evidence for 24 distinct FLA-DRB alleles. This variability, the complexity of clonal sequence analysis and its susceptibility to PCR-induced artefacts has represented a bottleneck to further progress. In this study we have applied reference strand-mediated conformational analysis (RSCA) to FLA-DRB. This protocol has been shown to be highly reproducible. Using five reference strands including two derived from non-domestic felines, we could distinguish 23 FLA-DRB alleles. We used RSCA to explore genetic polymorphism of FLA-DRB in 71 cats including 31 for which clonal sequence analysis was also available. On average, RSCA identified 0.9 more alleles within cats than clonal sequence analysis. Reference strand-mediated conformational analysis was also able to identify animals containing new alleles that could be targeted for sequence analysis. Analysis of allele patterns showed clear evidence for different allele distributions between breeds of cats, and suggested the Burmese breed may have highly restricted FLA-DRB polymorphism. Results from two families provided clear evidence for variation in the number of DRB genes on different haplotypes, with some haplotypes carrying two genes and some containing three. This study highlights the utility of RSCA for the resolution of complex amplicons containing up to six distinct alleles. A simple, rapid method for characterizing FLA-DRB makes possible studies on vaccine response and susceptibility/resistance to viral infections, which are a significant clinical problem in cats.     

Measurement of local cerebral blood flow with iodo [14C] antipyrine

The autoradiographic diffusible tracer technique for the measurement of local cerebral blood flow was originally designed for use with the radioactive, inert gas 131I-labeled trifluoroiodomethane and is applicable only with tracers that exhibit unrestricted diffusion through the blood-brain barrier. Because of the technical problems associated with the use of gaseous tracers, a suitable nonvolatile tracer has been sought. [14C] Antipyrine has been used previously and found to be unsuitable because of limitations in its diffusion through the blood-brain barrier. An analogue of [14C]antipyrine, iodo [14C]antipyrine, exhibits higher partition coefficients than [14C]antipyrine between nonpolar solvents and water and might, therefore, be expected to diffuse more freely through the barrier. Its use as the tracer in the local blood flow technique leads to values considerably above those obtained with [14C]antipyrine in the rat and cat and essentially the same as those obtained with the gas trifluoro[131I]iodomethane in the cat. Iodo[14C]antipyrine appears, therefore, to be a satisfactory nonvolatile tracer for the measurement of local cerebral blood flow.     

Definition of HLA-C alleles using sequence-specific oligonucleotide probes (PCR-SSOP)

Abstract: Many new HLA-C locus alleles have recently been identified by DNA sequencing, and a molecular based method for their detection using PCR with sequence specific primers has been reported. However, other methods may be more appropriate for the identification of C locus alleles in larger studies. Here we describe one such system, based on PCR sequence specific oligonucleotide probes, (SSOP) for C locus typing. Advantages of SSOP typing compared to SSP are that it is easier to detect new alleles, more cost effective and less time consuming. We have developed a DNA typing method to identify the broad C locus antigens (including those not yet defined serologically) using a minimum of probes with one amplification. We use a C locus specific sense primer in exon 2 and a consensus antisense primer in exon 3, in a two-step PCR, giving a product of 710 bp. Probes were designed with similar melting temperatures (54–56C) that would identify as many alleles as possible. The method was established using DNA from B lymphoid cell lines of known C locus type, mostly 10th workshop homozygous cell lines, plus as many other sequenced cell lines as possible. The system was able to correctly identify their C locus types using only 26 probes. DNA was tested from a panel of serologically typed individuals which included many different heterozygous combinations. We found a high concordance of results, with all discrepancies being additional antigens identified by molecular typing, filling in serological blanks. We can identify all common heterozygote combinations using this method.     

Peptide-based approaches to treat asthma, arthritis, other autoimmune diseases and pathologies of the central nervous system

In this review we focus on peptide- and peptidomimetic-based approaches that target autoimmune diseases and some pathologies of the central nervous system. Special attention is given to asthma, allergic rhinitis, osteoarthritis, and Alzheimer's disease, but other related pathologies are also reviewed, although to a lesser degree. Among others, drugs like Diacerhein and its active form Rhein, Pralnacasan, Anakinra (Kineret), Omalizumab, an antibody "BION-1", directed against the common beta-chain of cytokine receptors, are described below as well as attempts to target beta-amyloid peptide aggregation. Parts of the review are also dedicated to targeting of pathologic conditions in the brain and in other tissues with peptides as well as methods to deliver larger molecules through the "blood--brain barrier" by exploring receptor-mediated transport, or elsewhere in the body by using peptides as carriers through cellular membranes. In addition to highlighting current developments in the field, we also propose, for future drug targets, the components of the inflammasome protein complex, which is believed to initiate the activation of caspase- 1 dependent signaling events, as well as other pathways that signal inflammation. Thus we discuss the possibility of targeting inflammasome components for negative or positive modulation of an inflammatory response.     

Cellular localisation of HHV-8 in Castleman's disease: is there a link with lymph node vascularity?

AIMS: Human herpesvirus 8 (HHV-8) has been identified in multicentric Castleman's disease and in angioimmunoblastic lymphadenopathies. However, the presence of the virus does not necessarily indicate an aetiological role in these conditions. This study investigates the cell types infected by HHV-8 in Castleman's disease and examines the correlation between HHV-8 and Castleman's disease lymph node angiogenesis. METHODS: Sixteen formalin fixed, paraffin wax embedded samples from patients with Castleman's disease (six multicentric, 10 solitary) were examined for the presence of HHV-8 using the polymerase chain reaction (PCR), non-isotopic in situ hybridisation, PCR in situ hybridisation (PCR-ISH), and real time quantitative TaqMan PCR to HHV-8 open reading frame 26 (ORF-26), and viral (v)-cyclin encoding regions. Vascularity was assessed using CD34, CD31, and factor VIII immunocytochemistry, and lymph nodes were scored as "low" or "high". RESULTS: Five multicentric Castleman's disease and two solitary Castleman's disease biopsies were positive for HHV-8. HHV-8 was identified in approximately 10% of intranodal B lymphocytes, in endothelial cells, and in subcapsular spindle cell proliferations. The copy number of HHV-8 was low at 10-50 copies/1000 cells. The highest copy number was in subcapsular spindle cells. There was no correlation between vascularity score and HHV-8 status. CONCLUSION: The preferential localisation of HHV-8 in subcapsular spindle cell proliferations (where early intranodal Kaposi's sarcoma initiates) and endothelial cells in Castleman's disease might finally explain the link between intranodal Kaposi's sarcoma and Castleman's disease.     

Identification of HHV8 in early Kaposi''s sarcoma: implications for Kaposi''s sarcoma pathogenesis.

AIMS: Kaposi's sarcoma is a vascular tumour of uncertain pathogenesis possibly caused by an infectious agent, identified in high risk groups. Accumulating solution phase polymerase chain reaction (PCR) and seroepidemiological data suggest that a previously undescribed herpes DNA virus (human herpesvirus 8 (HHV8)) is the causative agent. Using a unique cohort of early Kaposi's sarcoma, the precise cell type infected with HHV8 in such lesions was identified to elucidate further the role of HHV8 in the pathobiology of Kaposi's sarcoma. METHODS: Sixteen cases of early Kaposi's sarcoma (derived from skin and lymph node) were assessed for the presence of HHV8 using both standard solution phase PCR and TaqMan PCR to the KS330 Bam region of HHV8. In situ amplification was also performed on a selected group in an attempt to identify the candidate infected cells. RESULTS: Using both conventional solution phase and TaqMan PCR, 87% of cases were positive. In addition, HHV8 amplicons were localised in situ to endothelial and spindle cell proliferations in early Kaposi's sarcoma. The HHV8 viral load varied from lesion to lesion. CONCLUSIONS: The presence of HHV8 in early lesions supports a role for HHV8 in the pathogenesis of Kaposi's sarcoma. Coupled with recent seroepidemiological studies, these results suggest that HHV8 is the aetiological agent of Kaposi's sarcoma. Its precise interaction with other factors known to be involved in the development of Kaposi's sarcoma, including cytokines and anti-apoptosis genes, requires elucidation.     

Measuring sleep habits without using a diary: the sleep timing questionnaire

STUDY OBJECTIVES: To develop a single-administration instrument yielding equivalent measures of sleep to those obtained from a formal (2-week) sleep diary. DESIGN & SETTING: A single-administration Sleep riming Questionnaire (STQ) is described (and reproduced in the Appendix). Test-retest reliability was examined in 40 subjects who were given the STQ on two occasions separated by less than 1 year. Convergent validity was measured both by comparing STO-derived measures with objective measures derived from wrist actigraphy (n=23) and by comparing STQ-derived measures with other subjective measures derived from a detailed 2-week sleep diary in two nonoverlapping samples (n=101, 93). Correlations of STQ measures with age and momingness-eveningness (chronotype) were also examined. SUBJECTS: The analyses used sample sizes of 40, 23, 101, and 93 (both genders, overall age range 20y-89y). Most subjects were healthy volunteers; some Study 4 subjects were patients (enrolled in research protocols). RESULTS: Test-retest reliability for the STQ was demonstrated for estimates of bedtime (r = 0.705, p < 0.001) and waketime (r = 0.826, p < 0.001). Convergent validity using wrist actigraphy was demonstrated by correlations of 0.592 (p < 0.005) for bedtime, and of 0.769 (p < 0.001) for waketime. Diary studies indicated STQ bedtime and waketime data to be highly correlated (at about 0.8) with those obtained from a formal 2-week sleep diary. The STQ also provided data on estimated sleep latency and wake after sleep onset (WASO), which correlated reliably (at about 0.7) with average nightly ratings of these variables from a 2-week sleep diary. Mean estimated values of sleep latency and WASO from the two instruments were within 1 minute of each other. ST-derived bedtimes and waketimes correlated with both age and chronotype in the expected direction (older subjects earlier, morning types earlier). CONCLUSION: The STQ may be a reliable valid measure of sleep timing that could provide a time-efficient alternative to traditional sleep diaries.     

COMP mutation screening as an aid for the clinical diagnosis and counselling of patients with a suspected diagnosis of pseudoachondroplasia or multiple epiphyseal dysplasia

The skeletal dysplasias are a clinically and genetically heterogeneous group of conditions affecting the development of the osseous skeleton and fall into the category of rare genetic diseases in which the diagnosis can be difficult for the nonexpert. Two such diseases are pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED), which result in varying degrees of short stature, joint pain and stiffness and often resulting in early onset osteoarthritis. PSACH and some forms of MED result from mutations in the cartilage oligomeric matrix protein (COMP) gene and to aid the clinical diagnosis and counselling of patients with a suspected diagnosis of PSACH or MED, we developed an efficient and accurate molecular diagnostic service for the COMP gene. In a 36-month period, 100 families were screened for a mutation in COMP and we identified disease-causing mutations in 78% of PSACH families and 36% of MED families. Furthermore, in several of these families, the identification of a disease-causing mutation provided information that was immediately used to direct reproductive decision-making.     

Clinical, biochemical and immunoelectron microscopical evidence of dual hormone production in a mammosomatotroph cell adenoma

This paper reports the occurrence of a rare, yet distinct pituitary adenoma which was surgically removed from a 42-year-old male with both clinical and biochemical evidence of acromegaly and mild hyperprolactinaemia. The monomorphic adenoma consisted of mature cells which were ultrastructurally indistinguishable from those of a prolactinoma. Electron immunocytochemistry, including a series of double-labelling techniques using selected colloidal gold particles as markers, indicated the presence of a pituitary adenoma in which the cells were capable of simultaneously producing growth hormone and prolactin and packaging them within the same secretory granule. This is thought to represent a mammosomatotroph cell adenoma.