Vascular tone pathway polymorphisms in relation to primary open-angle glaucoma.

AIMS: Vascular perfusion may be impaired in primary open-angle glaucoma (POAG); thus, we evaluated a panel of markers in vascular tone-regulating genes in relation to POAG. METHODS: We used Illumina 660W-Quad array genotype data and pooled P-values from 3108 POAG cases and 3430 controls from the combined National Eye Institute Glaucoma Human Genetics Collaboration consortium and Glaucoma Genes and Environment studies. Using information from previous literature and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, we compiled single-nucleotide polymorphisms (SNPs) in 186 vascular tone-regulating genes. We used the 'Pathway Analysis by Randomization Incorporating Structure' analysis software, which performed 1000 permutations to compare the overall pathway and selected genes with comparable randomly generated pathways and genes in their association with POAG. RESULTS: The vascular tone pathway was not associated with POAG overall or POAG subtypes, defined by the type of visual field loss (early paracentral loss (n=224 cases) or only peripheral loss (n=993 cases)) (permuted P≥0.20). In gene-based analyses, eight were associated with POAG overall at permuted P<0.001: PRKAA1, CAV1, ITPR3, EDNRB, GNB2, DNM2, HFE, and MYL9. Notably, six of these eight (the first six listed) code for factors involved in the endothelial nitric oxide synthase activity, and three of these six (CAV1, ITPR3, and EDNRB) were also associated with early paracentral loss at P<0.001, whereas none of the six genes reached P<0.001 for peripheral loss only. DISCUSSION: Although the assembled vascular tone SNP set was not associated with POAG, genes that code for local factors involved in setting vascular tone were associated with POAG.

Astrocyte elevated gene-1 contributes to the pathogenesis of neuroblastoma.

Neuroblastoma, derived from neural crest progenitor cells, is the most common extracranial solid tumor of childhood. Astrocyte elevated gene-1 (AEG-1) is a primary mediator of tumor progression and metastasis in several human cancers. In this study, we investigated the potential contribution of AEG-1 in human neuroblastoma pathogenesis. AEG-1 expression was significantly elevated in neuroblastoma patient-derived samples and neuroblastoma cell lines as compared with normal peripheral nerve tissues, normal astrocytes and immortalized melanocytes. Knockdown of AEG-1 by small interfering RNA reduced the tumorigenic properties of highly aggressive neuroblastoma cells. Conversely, over-expression of AEG-1 enhanced proliferation and expression of the transformed state in less aggressive neuroblastoma cells through activation of the phosphatidylinositol 3-kinase-Akt-signaling pathway and stabilization of MYCN. These provocative results indicate that AEG-1 may play a crucial role in the pathogenesis of neuroblastoma and could represent a potential target for therapeutic intervention.

Does the sexually transmitted infections foundation course deliver and change practice? Feedback from delegates 2002-2006.

SUMMARY: Attendees at Newcastle sexually transmitted infections foundation (STIF) courses since 2002 were sent a postal questionnaire to ascertain views about the course, its effect on practice and the desire for further education. Totally 156 forms were returned (48% response). The majority 97% were satisfied with the course, 97% wanted updates, 57% annually and 33% biennially. Following a STIF course, 69% provided HIV testing (only 14% of those, prior to attendance). However, only 39% routinely offered HIV testing and only 34% routinely offered syphilis testing to patients whom they considered to be at risk of a sexually transmitted infection. Common reasons for not offering testing were lack of time for counselling, lack of confidence, no perceived need or anonymity concerns resulting in referral to genitourinary medicine. This was despite training, which encourages routine HIV testing with a pretest discussion rather than 'counselling' and education about recent outbreaks of syphilis.

Condom use among high-risk heterosexual women with concurrent sexual partnerships, Houston, Texas, USA.

Concurrent sexual partnerships allow for enhanced transmission of sexually transmitted infections (STIs). Condom use dynamics in this context may be an important factor for transmission of HIV. We conducted a cross-sectional study to describe the frequency of concurrency among high-risk heterosexual women in Houston, Texas and determine the factors associated with condom use. A total of 553 participants were recruited using respondent-driven sampling and completed an anonymous questionnaire; 256 (49%) were identified as having a concurrent partnership. The prevalence of condom use at last sexual encounter was 26%. Women were significantly more likely to use condoms if their sexual encounter was with a casual partner and if alcohol and/or drugs were not used. The high prevalence of concurrent partnerships suggests the presence of a dense sexual network which may enable the rapid spread of STIs and HIV. The risk of transmission may be additionally increased due to the low prevalence of condom use.

Nail-patella syndrome and its association with glaucoma: a review of eight families.

BACKGROUND: Nail-patella syndrome (NPS) is a rare autosomal dominant syndrome, characterised by dysplasia of the nails, patellae, elbows and iliac horns. Mutations in the LMX1B gene were found in four North American families in whom glaucoma cosegregated with NPS. AIMS: To investigate the association of glaucoma with NPS in Australian families and to determine how common NPS is in Australia. METHODS: One family with NPS and glaucoma was identified from the Glaucoma Inheritance Study in Tasmania. A further 18 index cases of NPS were identified from the genetics database for southeastern Australia. Eight of these pedigrees were available for comprehensive glaucoma examination on available family members. DNA was sequenced for mutations in LMX1B. RESULTS: In total, 52 living cases of NPS were identified suggesting a minimum prevalence of at least 1 in 100 000. 32 subjects from eight NPS pedigrees (four familial and four sporadic cases) were examined. 14 subjects had NPS alone. 4 subjects had NPS and glaucoma or ocular hypertension. Five pedigrees with NPS had a reported family history of glaucoma, although some of these people with glaucoma did not have NPS. LMX1B mutations were identified in 5 of the 8 index cases-three sporadic and two familial. Two of the six (33%) participants over 40 years of age had developed glaucoma, showing increased risk of glaucoma in NPS. CONCLUSION: Patients with NPS should be examined regularly for glaucoma. However, because the families with NPS are ascertained primarily from young probands or probands who are isolated cases, the exact level of risk is unclear.

Extended visual fixation and distractibility in children from six to twenty-four months of age.

Distractibility during extended visual fixations in children 6 months to 2 years of age was examined. A children's Sesame Street movie (Follow That Bird) was presented to children (N = 40) for a minimum of 20 min while fixation was videotaped and heart rate was recorded. Distractors (computer-generated patterns or another Sesame Street movie) were presented on an adjacent television screen. Consistent with prior research with older preschool-age children, the latency to turn toward the distractor was a function of the length of the look occurring before distractor onset. For the period immediately before distractor onset, children had a greater sustained lowered heart rate for the trials on which they continued looking at the center television monitor than for the trials on which they looked toward the distractor. This pattern of distractibility suggests attention increases over the course of a look toward the television, and that heart rate changes reflect this increase in attention.

Can sodium valproate improve learning in children with epileptiform bursts but without clinical seizures?

This study aimed to determine whether sodium valproate (VPA) improves cognitive performance and behaviour in children with learning and behavioural problems associated with electrographic epileptiform discharges but without clinical seizures. A randomized, double-blind, single-crossover trial was carried out with VPA or placebo on eight participants with different learning and behaviour problems. Participants also underwent neuropsychological testing under video EEG and the parent and teacher Behaviour Check List (CBCL; Achenbach 1991a, b) during each treatment phase. Clinically none of the children improved on VPA. On formal testing children were more distractable, had increased delay in response time, and showed lower memory scores while on VPA. In addition, parents reported higher internalizing scores on the CBCL while children were on VPA. Our data do not support the use of VPA in similar patients.

Genetics and phenotypes of RPE65 mutations in inherited retinal degeneration.

PURPOSE: To characterize the spectrum of RPE65 mutations present in 453 patients with retinal dystrophy with an interest in understanding the range of functional deficits attributable to sequence variants in this gene. METHODS: The 14 exons of RPE65 were amplified by polymerase chain reaction (PCR) from patients' DNA and analyzed for sequence changes by single-strand conformation polymorphism (SSCP) and direct sequencing. Haplotype analysis was performed using RPE65 intragenic polymorphisms. Patients were examined clinically and with visual function tests. RESULTS: Twenty-one different disease-associated DNA sequence changes predicting missense or nonsense point mutations, insertions, deletions, and splice site defects in RPE65 were identified in 20 patients in homozygous or compound heterozygous form. In one patient, paternal uniparental isodisomy (UPD) of chromosome 1 resulted in homozygosity for a probable functional null allele. Eight of the disease-associated mutations (Y79H, E95Q, E102X, D167Y, 669delCA, IVS7+4a-->g, G436V, and G528V) and one mutation likely to be associated with disease (IVS6+5g-->a) have not been reported previously. The most commonly occurring sequence variant identified in the patients studied was the IVS1+5g-->a mutation, accounting for 9 of 40 (22.5%) total disease alleles. This splice site mutation, as well as R91W, the most common missense mutation, exists on at least two different genetic backgrounds. The phenotype resulting from RPE65 mutations appears to be relatively uniform and independent of mutation class, suggesting that most missense mutations (15 of 40 disease alleles [37.5%]) result in loss of function. At young ages, this group of patients has somewhat better subjective visual capacity than is typically associated with Leber congenital amaurosis (LCA) type I, with a number of patients retaining some useful visual function beyond the second decade of life. CONCLUSIONS: RPE65 mutations account for a significant percentage (11.4%) of disease alleles in patients with early-onset retinal degeneration. The identification and characterization of patients with RPE65 mutations is likely to represent an important resource for future trials of rational therapies for retinal degeneration.

Age-dependent prevalence of mutations at the GLC1A locus in primary open-angle glaucoma.

PURPOSE: To screen a population with primary open-angle glaucoma for mutations in the gene that encodes the trabecular meshwork inducible glucocorticoid response protein (TIGR), also known as myocilin (MYOC). METHODS: Ophthalmologic information was collected for study subjects with primary open-angle glaucoma and their relatives. Mutation screening of 74 primary open-angle glaucoma probands was conducted by sequencing TIGR/MYOC coding sequence and splice sites. RESULTS: In 23 families we detected 13 nonsynonymous sequence changes, nine of which appear to be mutations likely to cause or contribute to primary open-angle glaucoma. Two mutations, Arg272Gly and Ile499Ser, and one nonsynonymous sequence variant, Asn57Asp, are novel. We found mutations in nine of 25 juvenile glaucoma probands (36%) and two of 49 adult-onset glaucoma probands (4%). Age classification of families rather than individual probands revealed mutations in three of nine families with strictly juvenile primary open-angle glaucoma (33%), and no mutations in 39 families with strictly adult-onset primary open-angle glaucoma (0%). In families with mixed-onset primary open-angle glaucoma containing both juvenile primary open-angle glaucoma and adult-onset primary open-angle glaucoma cases, we found mutations in eight of 26 families (31%). CONCLUSIONS: Our data suggest that Gly252Arg, Arg272Gly, Glu323Lys, Gln368STOP, Pro370Leu, Thr377Met, Val426Phe, Ile477Asn, and Ile499Ser are likely to play roles that cause or contribute to the etiology of autosomal dominant primary open-angle glaucoma. Our finding of more TIGR/MYOC mutations in families with mixed-onset primary open-angle glaucoma than in the families with strictly adult-onset primary open-angle glaucoma implies that the presence of relatives with juvenile primary open-angle glaucoma in a family could be used as a basis for identifying a subset of the population with adult-onset primary open-angle glaucoma with higher prevalence of TIGR/MYOC mutations. To address this issue, and to refine estimations of mutation prevalence in these age-defined subpopulations, prospective study of a larger population ascertained entirely through adult-onset primary open-angle glaucoma probands will be needed.

Extended visual fixation in the early preschool years: look duration, heart rate changes, and attentional inertia.

Visual fixation in infants from 6 months to 2 years of age was examined for its fit to the theory of "attentional inertia." A children's movie ("Sesame Street" movie, "Follow that Bird") or an extended audiovisual stimulus (computer-generated patterns) was presented to 40 children for a minimum of 20 min while fixation was videotaped and heart rate (HR) was recorded. Consistent with attentional inertia theory, fixations toward the stimuli had a lognormal distribution, HR decreased over the course of a look, and HR returned to prestimulus levels immediately before look offset. Older children (18 months, 24 months) showed a distinction in the parameters describing the lognormal distribution for the "Sesame Street" movie and the audiovisual patterns, whereas younger children (6 months, 12 months) responded similarly to the two stimulus types. Fixation patterns of children in this age range suggest attention increases over the course of a look, and parameters consistent with attentional inertia theory differentially develop in this age range.

Development of multimodal attention in young infants: modification of the startle reflex by attention.

This study examined the effect of attention engagement to compound auditory-visual stimuli on the modification of the startle blink reflex in infants. Infants at 8, 14, 20, or 26 weeks of age were presented with interesting audiovisual stimuli. After stimulus onset, at delays defined by heart rate changes known to be associated with sustained attention or attention disengagement, blink reflexes were elicited by visual or auditory stimuli. Blink amplitude to either visual or auditory stimuli was enhanced when the infants were engaged in attention to the foreground auditory-visual stimuli relative to control trials with no foreground patterns. This enhancement of the blink amplitude increased from 8 to 26 weeks of age. In contrast to selective modality enhancement for single-modality foreground stimuli, these results show that these multimodal stimuli engage both visual and auditory attention systems in this age range.

Localizing the development of covert attention in infants with scalp event-related potentials.

This study examined covert shifts of attention in infants aged 14, 20, and 26 weeks of age with scalp-recorded event-related potentials (ERPs). The infants were tested in a spatial cuing procedure. The reaction time to localize the target showed covert attention shifts (e.g., response facilitation or inhibition of return depending on cue-target stimulus onset asynchrony). There was a larger P1 ERP component on the valid trials than on the invalid trials or on the no-cue control trials. Presaccadic ERP potentials in response to the target were larger when it was in the cued location than when it was in uncued locations. There were increases from 14 to 26 weeks of age in the amount of inhibition of return, in the post-target-onset P1 effect, and in the presaccadic ERP potentials. These results suggest that cortical development parallels the development of covert orienting of attention and saccade planning in infants in this age range.

Detecting Attention Deficit Hyperactivity Disorder in a communications clinic: diagnostic utility of the Gordon Diagnostic System.

This study examines the sensitivity, specificity, predictive values, and likelihood ratios of laboratory measures of attention and impulsivity (the Gordon Diagnostic System; GDS) in 99 school-aged boys with a history of suspected language disorders. Classification analyses comparing scores from these tests with parent and teacher ratings of attention deficit hyperactivity disorder (ADHD) symptoms revealed low positive predictive values (20.0% to 36.8%) and high negative predictive values (71.9% to 87.9%). Likelihood ratios for abnormal test scores were low to moderate (0.74 to 1.73), suggesting that these tests may not accurately identify children with ADHD. Likelihood ratios for normal scores were also low to moderate (0.41 to 1.16). These findings suggest that GDS scores have clinical utility in ruling out a diagnosis of ADHD, but not in confirming the diagnosis in a clinic population of boys with communicative disorders who are at risk for developing ADHD.

Novel mutations in XLRS1 causing retinoschisis, including first evidence of putative leader sequence change.

Juvenile retinoschisis is an X-linked recessive disease caused by mutations in the XLRS1 gene. We screened 31 new unrelated patients and families for XLRS1 mutations in addition to previously reported mutations for 60 of our families (Retinoschisis Consortium, Hum Mol Genet 1998;7:1185-1192). Twenty-three different mutations including 12 novel ones were identified in 28 patients. Mutations identified in this study include 19 missense mutations, two nonsense mutations, one intragenic deletion, four microdeletions, one insertion, and one intronic sequence substitution that is likely to result in a splice site defect. Two novel mutations, c.38T-->C (L13P) and c.667T-->C (C223R), respectively, present the first genetic evidence for the functional significance of the putative leader peptide sequence and for the functional significance at the carboxyl terminal of the XLRS1 protein beyond the discoidin domain. Mutations in 25 of the families were localized to exons 4-6, emphasizing the critical functional significance of the discoidin domain of the XLRS1 protein.

An orthopaedic scoring system for nail-patella syndrome and application to a kindred with variable expressivity and glaucoma.

To help determine whether there is a genetic basis to the substantial variability observed in nail-patella syndrome (NPS), we devised a scoring system that quantifies the severity of the orthopaedic characteristics in NPS. Use of this system to score affected members in three generations of a single kindred revealed wide variability of severity of orthopaedic findings both within and between generations. Genetic testing in this family supported, but did not prove, a previously reported theory that the severity of the NPS in the offspring is modulated by the allele contributed by the unaffected parent. Evaluation of nonorthopaedic characteristics revealed the presence of glaucoma and the absence of kidney disease in this family. It is important that patients with NPS be evaluated for renal disease and glaucoma.

A trabecular meshwork glucocorticoid response (TIGR) gene mutation affects translocational processing.

PURPOSE: To examine possible effects of the E323K mutation in the trabecular meshwork glucocorticoid response (TIGR) gene (also known as myocilin [MYOC]), using assays of translocational processing through the endoplasmic reticulum (ER). The E323K mutation was of particular interest, since the mutation shows a strong association with early onset open-angle glaucoma, but has a minimal predicted effect on protein structure. METHODS: Normal and mutant TIGR cDNA constructs were used to generate protein products in the presence of endoplasmic reticulum (ER) membranes, using an assay previously developed to detect alterations in the ER translocation function. "Paused" regions for potential protein modifications were defined by proteinase K (PK) sensitivity in the presence of ER membranes, with the ability to restart translocation when treated with EDTA. The effects of the E323K mutation were evaluated, as well as mutations located on either side of E323K (G246R, G364V, P370L) as the other mutations had substantial predicted structural changes in addition to clear disease associations. RESULTS: The native TIGR molecule was observed to have a paused region that corresponds to the region of highest olfactomedin (OLF) homology. The E323K mutation, located near the beginning of this region, dramatically altered the normal pattern of nascent proteins observed in the translocational pausing assay. A prominent band appeared with the E323K mutation, which could represent a new product or a marked enhancement of a faint band normally seen, approximately 3 kDa higher than the major paused band. The other TIGR mutants examined did not show this effect. CONCLUSIONS: The major translocational pause that starts near the beginning of the region of high OLF homology may help to explain the high frequency of glaucoma-associated mutations in this area. The observed effect of the E323K mutation on the products of translocational processing suggests a delay in the normal pausing process of TIGR biogenesis. This delay points to a potentially distinct pathogenic mechanism for E323K as compared with the other TIGR mutations so far evaluated.