Outcomes of low-vision services using optometric and multidisciplinary approaches: a non-randomized comparison

Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.     

Complete structure of the alpha B-crystallin gene: conservation of the exon-intron distribution in the two nonlinked alpha-crystallin genes.

We isolated bovine complementary DNA clones for the alpha A- and alpha B-crystallin subunits. The alpha B cDNA clone was used to isolate an alpha B-crystallin gene. This gene, derived from hamster, occurs as a single copy in the genome and is 3.2 kilobases long. The coding sequences are spread on three exons with a total length of 709 nucleotides. The exon-intron distribution of the hamster alpha B-crystallin gene is similar to that of the alpha A-crystallin gene except for the 69 nucleotides that specify the 23 "insert" residues of the alpha AIns chain by means of differential splicing. The 3' noncoding region of the alpha B mRNA (140 bases), which is short compared with the alpha A mRNA (520 bases), shows a remarkable homology between calf and hamster. Both alpha-crystallin cDNA clones have been used to assign the chromosomal location of the corresponding human genes with the aid of somatic cell hybrids. It is shown that the single-copy alpha A- and alpha B-crystallin genes are located on different chromosomes.     

Sex determination in platypus and echidna: autosomal location of <Emphasis Type="Italic">SOX3</Emphasis> confirms the absence of <Emphasis Type="Italic">SRY</Emphasis> from monotremes

In eutherian ('placental') mammals, sex is determined by the presence or absence of the Y chromosome-borne gene SRY, which triggers testis determination. Marsupials also have a Y-borne SRY gene, implying that this mechanism is ancestral to therians, the SRY gene having diverged from its X-borne homologue SOX3 at least 180 million years ago. The rare exceptions have clearly lost and replaced the SRY mechanism recently. Other vertebrate classes have a variety of sex-determining mechanisms, but none shares the therian SRY-driven XX female:XY male system. In monotreme mammals (platypus and echidna), which branched from the therian lineage 210 million years ago, no orthologue of SRY has been found. In this study we show that its partner SOX3 is autosomal in platypus and echidna, mapping among human X chromosome orthologues to platypus chromosome 6, and to the homologous chromosome 16 in echidna. The autosomal localization of SOX3 in monotreme mammals, as well as non-mammal vertebrates, implies that SRY is absent in Prototheria and evolved later in the therian lineage 210-180 million years ago. Sex determination in platypus and echidna must therefore depend on another male-determining gene(s) on the Y chromosomes, or on the different dosage of a gene(s) on the X chromosomes.     

Conservation of chromosome arrangement and position of the X in mammalian sperm suggests functional significance

We used chromosome painting to show directly that chromosomes occupy fixed positions in the nuclei of mammal but not chicken sperm. We found that the positions of homologous chromosomes are conserved in sperm of two marsupial species that diverged 50–60 million years ago. We also discovered that the X chromosome lies in the region that makes first contact with the egg in marsupial and monotreme mammals, as well as eutherians, and suggest that this position may be related to its propensity for inactivation, and its high rate of loss from ICSI embryos. We propose that nuclear architecture in sperm is important for spatial chromatin differentiation and normal development of the fertilized egg, and evolved along with mammal-specific regulatory systems such as X inactivation and genomic imprinting. This revised version was published online in July 2006 with corrections to the Cover Date.     

Bird-like sex chromosomes of platypus imply recent origin of mammal sex chromosomes

In therian mammals (placentals and marsupials), sex is determined by an XX female: XY male system, in which a gene (SRY) on the Y affects male determination. There is no equivalent in other amniotes, although some taxa (notably birds and snakes) have differentiated sex chromosomes. Birds have a ZW female: ZZ male system with no homology with mammal sex chromosomes, in which dosage of a Z-borne gene (possibly DMRT1) affects male determination. As the most basal mammal group, the egg-laying monotremes are ideal for determining how the therian XY system evolved. The platypus has an extraordinary sex chromosome complex, in which five X and five Y chromosomes pair in a translocation chain of alternating X and Y chromosomes. We used physical mapping to identify genes on the pairing regions between adjacent X and Y chromosomes. Most significantly, comparative mapping shows that, contrary to earlier reports, there is no homology between the platypus and therian X chromosomes. Orthologs of genes in the conserved region of the human X (including SOX3, the gene from which SRY evolved) all map to platypus chromosome 6, which therefore represents the ancestral autosome from which the therian X and Y pair derived. Rather, the platypus X chromosomes have substantial homology with the bird Z chromosome (including DMRT1) and to segments syntenic with this region in the human genome. Thus, platypus sex chromosomes have strong homology with bird, but not to therian sex chromosomes, implying that the therian X and Y chromosomes (and the SRY gene) evolved from an autosomal pair after the divergence of monotremes only 166 million years ago. Therefore, the therian X and Y are more than 145 million years younger than previously thought.     

Anger: Cause or Consequence of Posttraumatic Stress? A Prospective Study of Dutch Soldiers

Many studies have shown that individuals with posttraumatic stress disorder (PTSD) experience more anger over time and across situations (i.e., trait anger) than trauma‐exposed individuals without PTSD. There is a lack of prospective research, however, that considers anger levels before trauma exposure. The aim of this study was to prospectively assess the relationship between trait anger and PTSD symptoms, with several known risk factors, including baseline symptoms, neuroticism, and stressor severity in the model. Participants were 249 Dutch soldiers tested approximately 2 months before and approximately 2 months and 9 months after their deployment to Afghanistan. Trait anger and PTSD symptom severity were measured at all assessments. Structural equation modeling including cross‐lagged effects showed that higher trait anger before deployment predicted higher PTSD symptoms 2 months after deployment (β = .36), with stressor severity and baseline symptoms in the model, but not with neuroticism in the model. Trait anger at 2 months postdeployment did not predict PTSD symptom severity at 9 months, and PTSD symptom severity 2 months postdeployment did not predict subsequent trait anger scores. Findings suggest that trait anger may be a pretrauma vulnerability factor for PTSD symptoms, but does not add variance beyond the effect of neuroticism.     

Visual Functioning Questionnaire: reevaluation of psychometric properties for a group of working-age adults.

PURPOSE: The Visual Functioning Questionnaire (VFQ-25) is one of the most widely used measures of vision-related quality of life. However, the questionnaire does not meet some psychometric quality criteria. The objectives of this study were first to obtain the factor structure of the VFQ-25, and second, to obtain interval scales by Rasch analysis. METHODS: The questionnaire was administered to 129 visually impaired adults (mean age 42.1 years; range 21 to 67 years). First, the items of the VFQ-25 were subjected to an exploratory factor analysis with Promax rotation. Next, we performed a separate Rasch analysis on each factor. We examined step thresholds and goodness of fit statistics of the items. Finally, we examined differential item functioning. RESULTS: Factor analysis indicated four factors: Near Activities, Distance Activities and Mobility, Mental Health and Dependency, and Pain and Discomfort. They accounted for 46.37% of the total variance. Most items showed some degree of disordering. After collapsing response categories, all items showed ordered thresholds. The Near Activities domain showed excellent fit, whereas the Distance Activities and Mobility domain, the Mental Health and Dependency domain, and the Pain and Discomfort domain had an unsatisfactory fit. There were two items showing uniform differential item functioning. CONCLUSIONS: The four-factor structure of the VFQ-25 largely confirms the structure of the questionnaire. However, the results of this study suggest that modifications of the original VFQ-25 structure are necessary.     

Diabetes mellitus: a risk factor affecting visual outcome in branch retinal vein occlusion

PURPOSE: The prognosis of visual acuity (VA) after branch retinal vein occlusion (BRVO) in patients with diabetes mellitus is unknown compared to the VA in non-diabetic patients with BRVO. The aim of this study was to evaluate the visual outcome of BRVO in diabetic and non-diabetic patients. METHODS: A retrospective case-control study of diabetic and non-diabetic patients with BRVO was performed. VA and commonly known risk factors and complications of BRVO were compared in a follow-up period of at least 1 year. RESULTS: A total of 28 eyes of patients with diabetes and 49 eyes of non-diabetic patients with BRVO were included. One year after BRVO, the VA in the patients with diabetes decreased significantly more than that of the non-diabetic patients. During the second year after BRVO, the VA did not change significantly in either group. BRVO in patients with diabetes occurs at an earlier age. Diabetic patients needed more outpatient visits. CONCLUSIONS: The VA 1 year after BRVO in patients with diabetes is worse compared to the VA in patients without diabetes. The VA stabilizes 1 year after onset in both groups. Diabetic patients tend to need more frequent follow-up in order to treat the sequelae of BRVO.     

Transconjunctival reopening of an occluded filtration fistula with the Q-switched Neodymium-YAG laser

The Q-switched neodymium-YAG laser was used via a transconjunctival approach to reopen a failed filtering bleb, 6 weeks after a primarily successful trabeculectomy had failed. One day after treatment, the intraocular pressure had decreased from 34 mm Hg to 17 mm Hg, and a conjunctival bleb had reformed.