Predictive testing for Huntington's disease: I. Predictors of uptake in South Wales

In Wales, predictive testing for Huntington's disease (HD) has not been offered proactively to families and uptake of testing is low in comparison to other centres. Little is known of those not requesting testing, particularly those not in direct contact with the genetics service. This study examined differences between a cohort of 22 test applicants and a random group of 32 'non-requesters', drawn from the South Wales HD register. Respondents were interviewed by means of a semi-structured schedule in their own homes. The study groups differed significantly on a number of variables including: knowledge of the availability of testing; perceived attitudes of family members and significant others to testing; length of knowledge and perceived stressfulness of being at risk; and perceived ability to cope with an unfavourable result. Overall, knowledge of testing procedures was poor and at-risk individuals' understanding of genetic terminology was at odds with scientific distinctions. Discussion focuses on the organisational and psychological factors associated with lack of knowledge of the availability of testing and the interpretation of reported coping capacities.     

Prediction of global outcome with acute neuropsychological testing following closed-head injury.

Delaying assessment until emergence from post-traumatic amnesia increases completion rates, but this practice causes variable time delays from the date of injury to testing, which can complicate the interpretation of research findings. In the current study, the performance of 105 head injury survivors on simple tests of language comprehension and attention was used to predict global outcome. It was hypothesized that 1 month performance on these measures would aid in the prediction of Disability Rating Scale (DRS) and Glasgow Outcome Scale (GOS) scores collected at 6 months post injury. Only raw scores on the modified Test of Complex Ideational Material accounted for a significant amount of the variance in DRS scores (4.4%) above that accounted for by age, education, Glasgow Coma Scale score, and pupil response. However, testability at 1 month post injury on all four tests consistently accounted for a larger portion of the variance in DRS scores (10.1-13.2%) and significantly improved prediction of GOS scores. Galveston Orientation and Amnesia Test scores collected at 1 month post injury accounted for substantially less variance in DRS scores (7.7-8.4%). Neuropsychological data, including the testability of patients, collected uniformly at 1 month following injury can contribute to the prediction of global outcome.     

An AscI boundary library for the studies of genetic and epigenetic alterations in CpG islands

Knudson's two-hit hypothesis postulates that genetic alterations in both alleles are required for the inactivation of tumor-suppressor genes. Genetic alterations include small or large deletions and mutations. Over the past years, it has become clear that epigenetic alterations such as DNA methylation are additional mechanisms for gene silencing. Restriction Landmark Genomic Scanning (RLGS) is a two-dimensional gel electrophoresis that assesses the methylation status of thousands of CpG islands. RLGS has been applied successfully to scan cancer genomes for aberrant DNA methylation patterns. So far, the majority of this work was done using NotI as the restriction landmark site. Here, we describe the development of RLGS using AscI as the restriction landmark site for genome-wide scans of cancer genomes. The availability of AscI as a restriction landmark for RLGS allows for scanning almost twice as many CpG islands in the human genome compared with using NotI only. We describe the development of an AscI-EcoRV boundary library that supports the cloning of novel methylated genes. Feasibility of this system is shown in three tumor types, medulloblastomas, lung cancers, and head and neck cancers. We report the cloning of 178 AscI RLGS fragments via two methods by use of this library.     

SUMO modification of a novel MAR-binding protein, SATB2, modulates immunoglobulin mu gene expression

Nuclear matrix attachment regions (MARs) are regulatory DNA sequences that are important for higher-order chromatin organization, long-range enhancer function, and extension of chromatin modifications. Here we characterize a novel cell type-specific MAR-binding protein, SATB2, which binds to the MARs of the endogenous immunoglobulin micro locus in pre-B cells and enhances gene expression. We found that SATB2 differs from the closely related thymocyte-specific protein SATB1 by modifications of two lysines with the small ubiquitive related modifier (SUMO), which are augmented specifically by the SUMO E3 ligase PIAS1. Mutations of the SUMO conjugation sites of SATB2 enhance its activation potential and association with endogenous MARs in vivo, whereas N-terminal fusions with SUMO1 or SUMO3 decrease SATB2-mediated gene activation. Sumoylation is also involved in targeting SATB2 to the nuclear periphery, raising the possibility that this reversible modification of a MAR-binding protein may contribute to the modulation of subnuclear DNA localization.     

Monoclonal Antibodies to Trypanosoma cruzi Inhibit Motility and Nucleic Acid Synthesis of Culture Forms

Monoclonal antibodies were raised against the surface of epimastigotes and metacylic trypomastigotes of Trypanosoma cruzi, as shown by electron microscopy, agglutination, and immunofluorescence. The antibodies were stage specific but not strain specific. A deleterious effect of the antibodies on T. cruzi culture forms was shown by the drastic reduction of parasite motility and incorporation of nucleic acid precursors. Some fraction of the parasite population, however, was viable and replicated and infected mouse macrophages in culture. The antibodies were found to also mediate complement-induced lysis of culture forms of T. cruzi.     

Cell extract-derived differentiation of embryonic stem cells

Various means have been used to encourage the differentiation of embryonic stem cells (ESCs) toward specific lineages, including growth factor administration, genetic modification, and coculture with relevant cells/tissues. Cell extract-based reprogramming has recently been used to derive mature cells from nonrelated phenotypes. In this communication, we tested whether this in vitro reprogramming approach can be used to direct ESC differentiation. Permeabilized murine ESCs exposed to extracts of murine type II pneumocytes showed increased expression of surfactant protein C and its corresponding mRNA, reflecting enhanced differentiation of pneumocytes. Subsequent differentiation to a type I phenotype was demonstrated by expression of aquaporin 5. Pneumocyte formation occurred quicker than with growth factor-induced differentiation. Our findings establish that ESCs can be differentiated in vitro using cellular extracts. This model provides a tool for analysis of the key factors involved in the differentiation of ESCs to type II pneumocytes.     

Implications of pharmacogenetics for individualizing drug treatment and for study design

Adverse drug reactions and ineffective drug treatment are responsible for a large health care burden. Considerable variability in drug response makes the prediction of the individual reaction difficult. Pharmacogenetics can help to individualize drug treatment in accordance with the genetic make-up of the patient. Drug response is best understood as a complex interplay between pharmacokinetics, pharmacodynamics, and other disease-associated factors. There are a large number of genetic variants in the enzymes of phase I and phase II drug metabolism, in drug transporters, and drug targets, all of which account for differences in drug response. The polymorphisms in the cytochrome P450 enzyme system have been investigated most extensively. Genotype-based dose adjustment which should ensure "bioequivalent" drug concentrations in all patients has been derived from pharmacokinetic parameters, but this approach will have to be verified in prospective studies. Drug transport has recently been recognized as a further crucial determinant in pharmacokinetics. The effect of genetics on disease susceptibility and drug treatment has been studied quite extensively; however, hardly any of this progress is at present reflected in routine health care. The integration of pharmacogenetic factors in clinical trials requires novel considerations for study design and data interpretation. It is to be hoped that the new science bioinformatics will (a) help us identify the contribution of genetics to disease and treatment response and will (b) create data-processing devices which help the physician in the face of the enormously expanding scientific knowledge in selecting the best individually adapted treatment for the patient.     

Engulfment of mast cell secretory granules on skin inflammation boosts dendritic cell migration and priming efficiency

1. Download : Download high-res image (228KB)
2. Download : Download full-size image

     

Early increase precedes a depletion of VIP and PGP-9.5 in the skin of insulin-dependent diabetics—correlation between quantitative immunohistochemistry and clinical assessment of peripheral neuropathy

Diabetic neuropathy affects both sensory and autonomic peripheral nerve fibres. Vasoactive intestinal polypeptide (VIP) is present in autonomic fibres which modulate sweat secretion, while calcitonin gene-related peptide (CGRP) is localized to cutaneous sensory fibres. In this study, immunohistochemistry and image analysis were used to assess changes of VIP and CGRP, and of the pan-neuronal marker protein gene-product (PGP)-9.5, in skin biopsies of 18 patients affected by type 1 diabetes (age range 18–46 years) and from seven aged-matched controls. Patients were divided into three groups: group 1 (n=6), with diabetes for 6 months to 3 years; group 2 (n=5), with the disease for 5–10 years; and group 3 (n=7), with diabetes for more than 10 years. VIP immunoreactivity (IR) and PGP-9.5-IR were significantly reduced around sweat glands (P <0.005) in groups 2 and 3. Epidermal CGRP-IR and PGP-9.5-IR were significantly reduced in group 3 (P <0.05). Twenty-eight per cent (5/18) of all patients showed high VIP-IR around sweat glands (>95 per cent confidence limits of controls) and all of these patients had diabetes for less than 3 years. Conversely, 55 per cent (10/18) of patients had low VIP-IR (<5 per cent confidence limit of controls). The latter, compared with the former, showed a significantly longer duration of diabetes (Fisher exact test P=0·002), presence of clinical autonomic neuropathy (Fisher exact test P=0.04), and a reduced sural nerve conduction velocity (Fisher exact test P=0.04). These results suggest that quantitative immunohistochemical analysis of peptide-containing cutaneous nerves allows an objective evaluation of nerve fibre alterations at early stages of diabetes than is currently possible with neurophysiological functional tests.