New pathologic mechanisms in nucleotide repeat expansion disorders

Tandem microsatellite repeats are common throughout the human genome and intrinsically unstable, exhibiting expansions and contractions both somatically and across generations. Instability in a small subset of these repeats are currently linked to human disease, although recent findings suggest more disease-causing repeats await discovery. These nucleotide repeat expansion disorders (NREDs) primarily affect the nervous system and commonly lead to neurodegeneration through toxic protein gain-of-function, protein loss-of-function, and toxic RNA gain-of-function mechanisms. However, the lines between these categories have blurred with recent findings of unconventional Repeat Associated Non-AUG (RAN) translation from putatively non-coding regions of the genome. Here we review two emerging topics in NREDs: 1) The mechanisms by which RAN translation occurs and its role in disease pathogenesis and 2) How nucleotide repeats as RNA and translated proteins influence liquid-liquid phase separation, membraneless organelle dynamics, and nucleocytoplasmic transport. We examine these topics with a particular eye on two repeats: the CGG repeat expansion responsible for Fragile X syndrome and Fragile X-associated Tremor Ataxia Syndrome (FXTAS) and the intronic GGGGCC repeat expansion in C9orf72, the most common inherited cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Our thesis is that these emerging disease mechanisms can inform a broader understanding of the native roles of microsatellites in cellular function and that aberrations in these native processes provide clues to novel therapeutic strategies for these currently untreatable disorders.

Occurrence of Coffee ringspot virus, a Brevipalpus Miteborne Virus in Coffee in Costa Rica

Coffee ringspot virus (CoRSV) (family Rhabdoviridae) is transmitted by Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae). Coffee ringspot disease was first reported in coffee plants from Brazil in 1939 (1). In August 2000, severe symptoms of concentric ringspots and "oak leaf" patterns on coffee leaves (Coffea arabica L. cv. Catuai) were observed during field inspections conducted in two areas of San Gabriel de Desamparados, Costa Rica. The disease caused premature fruit and leaf drop in the affected plants. Some areas within the ringspot lesions remained green on senescent leaves. Because CoRSV particles remain restricted to lesion areas (1), this virus has not been purified, and antiserum for virus detection is not available. Therefore, leaves with symptoms were collected and examined by transmission electron microscopy. In ultrathin sections of symptomatic leaves, arrays of rhabdovirus-like particles were associated with the nucleus as described for CoRSV (2). Healthy tissues did not contain similar arrays of bacilliform and bullet-shaped particles. Twenty mites collected from the infected plants at the same locations and time were slide-mounted and identified as B. phoenicis. High populations of this mite were also observed infesting plants of Cajanus cajan L. that were intercropped with coffee at the same location. Sweet orange trees growing in the same fields as shade for the coffee did not show symptoms of citrus leprosis, a disease caused by another Brevipalpus-transmitted virus that was recently reported in Panama (3). To our knowledge, this is the first report of a virus similar to CoRSV in Costa Rica. The spread of this virus, presumably CoRSV, could seriously affect the coffee industry throughout Central America by increasing production costs. It may be necessary to apply one or more foliar acaricides to effectively control the mite vector. References: (1) A. Bitancourt. O. Biol. 5:33, 1939. (2) C. M. Chagas et al. Phytopathol. Z. 102:100, 1981. (3) F. S. Dominguez et al. Plant Dis. 85:228, 2001.

Expression of the lipocalin-type prostaglandin D synthase gene in the reproductive tracts of Holstein bulls

The aim of this study was to localize expression of the prostaglandin D synthase gene in the reproductive tracts of Holstein bulls using northern blotting and in situ hybridization. For northern blotting, a digoxigenin-labelled prostaglandin D synthase cDNA probe was used to probe blots containing RNA isolated from the testes, epididymides, vas deferens, ampullae, seminal vesicles, prostate and bulbourethral glands of bulls. The digoxigenin-labelled cDNA for the bovine homologue of prostaglandin D synthase hybridized to a single band (approximately 0.9 kb) to RNA samples from the caput, corpus and cauda epididymides, as well as RNA samples from the vas deferens and the ampulla. The probe also detected a single band in testis samples, although the transcript size was slightly larger (approximately 1.0 kb) than the transcript found in the other tissues. The highest expression of prostaglandin D synthase was observed in the testes and caput epididymides. Prostaglandin D synthase transcripts were not found in the seminal vesicles or the prostate or bulbourethral glands using northern blotting. For in situ hybridization, antisense and sense riboprobes were synthesized and used to hybridize to cryosections obtained from the reproductive tissues of bulls. In situ hybridization of bull testes showed that prostaglandin D synthase transcripts were present within the germ cells in the adluminal compartment of the seminiferous tubules containing round and elongated spermatids, indicating that expression varied with stage of development of the seminiferous tubules. Prostaglandin D synthase expression was observed in the epithelial cells of the epididymides with greatest expression occurring in the caput epididymidis. Some expression was also observed in the epithelial cells of the vas deferens and a few cells of some lobules in the prostate and bulbourethral glands. Expression of the prostaglandin D synthase gene was not detected in ampullae or seminal vesicles by in situ hybridization.

Predictors of parents' physical disciplinary practices

OBJECTIVE

This study examined how childhood history of discipline (1) related to ratings of how severe and typical punishments were; and (2) predicted parents' use of discipline techniques. The influence of child culpability on these ratings was also investigated.

METHOD

Ninety-nine New Zealand parents rated 12 physical discipline scenarios varying in discipline severity and perceived child culpability. Parents judged how severe and typical they considered the disciplines depicted in the scenarios and reported on how often they had experienced such discipline as children and how often they had used them with their own children.

RESULTS

When the child was perceived to be at fault, parents rated the discipline depicted as less severe, considered the technique more typical, reported they had been similarly disciplined more frequently, and applied such discipline to their child more frequently. Childhood history of a discipline was related to the parent's use of that method, and the parents judged techniques they used with their own children as less severe and more typical of methods of discipline. History of discipline and severity judgments were the best predictors of parents' disciplinary practices.

CONCLUSIONS

Although the findings support the cycle of violence theory, more complex potential pathways to abusive parenting, including the variables in this study, are proposed.

The Arabidopsis thaliana cDNAs coding for eIF4E and eIF(iso)4E are not functionally equivalent for yeast complementation and are differentially expressed during plant development

Two cDNAs (At.EIF4E1 and At.EIF4E2) encoding, respectively, the eukaryotic initiation factors eIF4E and eIF(iso)4E of Arabidopsis thaliana were isolated by complementation of a Saccharomyces cerevisiae conditional mutant. The deduced amino acid sequences of the proteins are homologous to those from monocotyledonous plants, yeast and mammals. The corresponding genes were identified in YAC clones mapping to chromosome IV (At.EIF4E1) and to chromosome V (At.EIF4E2). The yeast strain complemented by At.EIF4E2 grew poorly compared with an isogenic strain expressing At.EIF4E1. Northern and in situ hybridization analysis show that both Arabidopsis At.EIF4E1 and At.EIF4E2 mRNAs are differentially accumulated in plant tissues. The At.EIF4E1 mRNA is expressed in all tissues except in the cells of the specialization zone of the roots; the At.EIF4E2 mRNA is particularly abundant in floral organs and in young developing tissues. This work further demonstrates an association between a high level of EIF4E mRNAs and cell proliferation and suggests that the plant eIF4E isoforms may have distinct functions in cell development and metabolism.

Parenting stress and anger expression as predictors of child abuse potential

To explore one potential pathway to physical child abuse, the present investigation used hierarchical regression analysis using measures of parenting stress and anger expression to jointly predict child abuse potential. The Parenting Stress Index, State-Trait Anger Expression Inventory, and the Child Abuse Potential Inventory were administered to two different samples of New Zealand parents. As expected, both studies revealed parenting stress and anger expression and were individually positively correlated with child abuse potential: the major finding involved the strong point contribution of parenting stress and anger expression in predicting Child Abuse Potential Inventory scores. Application of findings for intervention and prevention are discussed.

Lymphocyte subset determination using a hematology analyzer

Anti-CD4 antibody (T4)-coated microspheres were used to label CD4 cells in whole blood. The mixture was lysed and analyzed by a modified Coulter VCS hematology analyzer, which differentiated microsphere-labeled cells by a change in Coulter volume, conductance, and light scatter. %CD3+/CD4+ fluorescent values from a profile were compared to %CD4 values using the VCS-microsphere method. CD3 gating was used to exclude CD4+ monocytes from the 90LS-FALS lymphocyte gate. The results correlated well (R = 0.996). The percentage of CD4+ lymphocytes from profile scatterplots and VCS scatterplots showed a line of regression close to the equivalence line (n = 76, slope = 0.96) when CD3 gating was used for the profile. These results suggest that CD3 gating, though necessary for 90LS-FALS scatterplots, may not be necessary for volume-conductance-light scatterplots.

Helicobacter pylori in dyspeptic children and adults: endoscopic, bacteriologic and histologic correlations

Using different bacteriological (urease test, Gram staining and culture) and histological (Steiner staining and modified Giemsa staining) techniques, we searched for the presence of Helicobacter pylori in the gastric antrum of 200 dyspeptic Brazilian patients (106 females and 94 males aged 19 days to 81 years). The presence of bacteria was then correlated with the endoscopic and histological findings. H. pylori was present in 59.5% of the population studied. In Brazil, colonization occurs early, involving 37% of the dyspeptic population by 20 years of age. The presence of H. pylori in the gastric antrum was strongly associated with duodenal ulcer (P < 0.001) and a normal endoscopic examination did not exclude the possibility of colonization of the gastric antrum by H. pylori. The most sensitive test was the preformed urease test (89%). We conclude that more than one diagnostic method should preferably be used for the detection of H. pylori and that the presence of H. pylori is closely correlated with active chronic gastritis (P < 0.001).

Behavioral upset in medical patients--revised: evaluation of a parent report measure of distress for pediatric populations

Examined the utility of a new parent-report measure designed specifically for pediatric inpatients, the Behavioral Upset in Medical Patients-Revised (BUMP-R). The BUMP-R was administered to 151 mothers of hospitalized children ages 4-12 years the day following the child's hospital admission. The BUMP-R demonstrated good internal consistency and a factor analysis revealed four factors identified as negativity/agitation, amiability, dysphoria, and noncompliance. Children exhibiting behavioral distress at home were more likely to experience adjustment problems upon hospitalization. Demographic and illness-related variables were not substantial risk factors for hospital adjustment difficulties.

Factors associated with the acceptance of Norplant or IUD among women with similar socio-demographic characteristics

The purpose of this study was to identify factors that explain why women who consulted at the same clinic, went through the same counseling procedure and who had no contraindications for using Norplant decided to use another long-acting method, the IUD. Subjects were women who consulted at the Family Planning Clinic, State University of Campinas Hospital. One hundred Norplant acceptors and 100 IUD acceptors were interviewed at home, by trained interviewers who were not related to the clinic. Four out of five Norplant acceptors and all IUD acceptors had learned about the method chosen before attending the clinic. Results suggest that among IUD users there were more women who did not like the idea of taking a hormone or medicine to prevent pregnancy, while Norplant acceptors were more willing to try new experiences. Half the Norplant acceptors had learned about the method through TV, compared to 12% of IUD acceptors. Counseling at the clinic was not a determining factor, though it is important to clarify clients' doubts.

Two-dimensional impedance studies of BSA buoyant density separated human erythrocytes

Combined DC (Coulter Volume) and radio frequency impedance studies were performed on human erythrocytes which had been separated by buoyant density in linear, neutral, isotonic bovine serum albumin gradients. The individual buoyant density fractions showed no reproducible shift in volume with buoyant density but did show a shift with opacity, radio frequency impedance divided by dc impedance. This new electronic parameter of opacity can be related to cell age, since both it and cell age are directly related to buoyant density. This increase in opacity with buoyant density is correlated with a change in shape.