Further evidence of pleiotropy influencing speech and language: analysis of the DYX8 region

BACKGROUND/AIMS

Genetic studies have raised the possibility of common bases for cognitive linguistic disorders such as speech sound disorder (SSD), reading disorder (RD) and language impairment (LI). Thus, some of the same genes may jointly influence cognitive components within and between these three disorders. We examined the plausibility of this theory in a sample of families ascertained on the basis of a child with SSD.

METHODS

Using the method of generalized estimating equations to solve a bivariate family predictive model we obtained measures of comorbidity and familial aggregation of SSD and LI. We then used two methods of multipoint model-free linkage analysis to evaluate SSD and LI psychometric test measures over a region previously implicated in linkage studies of RD, DYX8 region, 1p34-p36.

RESULTS

Bivariate phenotypic analyses show evidence of comorbidity and within family aggregation and coaggregation of SSD and LI. In addition, two regions on chromosome 1 show suggestive evidence of linkage. The first region was previously reported in dyslexia studies. Our maximum linkage signal in this region measured articulation (p = 0.0009) in SSD sibling pairs. The second region is characterized by processes involved in language production, with the maximum linkage signal measuring listening comprehension (p = 0.0019) using all sibling pairs.

CONCLUSION

We conclude that the DYX8 region could bear genes controlling pleiotropic effects on SSD, LI and RD.

Economic evaluation of neonatal screening for phenylketonuria and congenital hypothyroidism

OBJECTIVE

To evaluate the costs and benefits of neonatal screening for phenylketonuria (PKU) and congenital hypothyroidism (CH). Neonatal screening for PKU and CH is common throughout the developed world. It represents a model of preventive care in that the screening procedure is simple and intellectual disability is otherwise irreversible. Changes in treatment and care, and in particular the advent of maternal PKU, require regular evaluation of a programme that also impacts on a large healthy population.

METHOD

Costs of screening were based on the programme provided within Western Australia. Costs averted were derived using patterns of care currently adopted in Western Australia and applied according to historical patterns of intellectual disability for each condition.

RESULTS

A net saving of dollar A2.9 million is attributable to the programme annually. The economic benefits derive from the prevention of intellectual disability which otherwise incurs costs throughout the life of the affected individual. Maternal PKU represented a minor proportion of overall costs. Sensitivity analysis showed that the cost savings were robust, given changes in the levels of intellectual disability, but varied according to the discount rate. The result of a net saving was evident under all assumptions.

CONCLUSION

Neonatal screening for PKU and CH is a cost saving use of resources and the emergence of maternal PKU has not had a significant effect on the economic outcomes.

Canine transposition following trauma and loss of a central incisor: treatment options

The aim of this article is to make clinicians aware of the possibility of canine transposition following loss of the upper central incisor. Using two case reports it considers the opportunities for rehabilitation of the occlusion, and discusses surgical, orthodontic and restorative considerations.

Improved measurement of the K+-->pi+nunu; branching ratio

An additional event near the upper kinematic limit for K+-->pi(+)nunu; has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nunu;)=(1.47(+1.30)(-0.89))x10(-10) based on three events observed in the pion momentum region 211<P<229 MeV/c. At the measured central value of the branching ratio, the additional event had a signal-to-background ratio of 0.9.

Interferon- -1b slows progression of atrophy in RRMS: Three-year follow-up in NAb- and NAb+ patients

OBJECTIVE

To determine the effect of interferon-beta-1b (IFNbeta-1b) treatment on total contrast-enhancing lesions (CEL), white matter lesion load (WMLL), and cerebral atrophy (CA) in patients with relapsing-remitting multiple sclerosis (RRMS) using serial monthly MRI.

METHODS

An open-label baseline-vs-treatment crossover trial was conducted with 30 RRMS patients monitored during a 6-month baseline and up to 36 months on treatment with IFNbeta-1b. Monthly MRI exams and neurologic exams using the Expanded Disability Status Scale (EDSS) were performed.

RESULTS

The percentage changes from baseline for years 1, 2, and 3 on IFNbeta-1b were as follows: brain volume (BV) = -1.35, -1.48, and -1.68%; CEL = -76.5, -60.1, and -54.7%; WMLL = -12.2, -9.8, and -10.4%. There was no difference in the BV, CEL, or WMLL for between-year comparisons, and the decrease in BV from year 1 to years 2 and 3 was less than the change from baseline to year 1. EDSS did increase (p < 0.001) when comparing the last 3 months of baseline (2.8 +/- 2.1) and the last 3 months on IFNbeta-1b (3.6 +/- 2.1). Eleven patients developed neutralizing antibody (NAb) during the study. The effect of IFNbeta-1b on CEL and WMLL was significantly reduced in NAb+ patients compared with NAb- patients (p < 0.003).

CONCLUSION

IFNbeta-1b decreases contrast-enhancing lesions and white matter lesion load over 3 years on therapy and slows the progression in cerebral atrophy during years 2 and 3.

Exposure of aircraft crew to cosmic radiation: on-board intercomparison of various dosemeters

Owing to their professional activity, flight crews may receive a dose of some millisieverts within a year; airline passengers may also be concerned. The effective dose is to be estimated using various experimental and calculation tools. The European project DOSMAX (Dosimetry of Aircrew Exposure during Solar Maximum) was initiated in 2000 extending to 2004 to complete studies over the current solar cycle during the solar maximum phase. To compare various dosemeters in real conditions simultaneously in the same radiation field, an intercomparison was organised aboard a Paris-Tokyo round-trip flight. Both passive and active detectors were used. Good agreement was observed for instruments determining the different components of the radiation field; the mean ambient dose equivalent for the round trip was 129 +/- 10 microSv. The agreement of values obtained for the total dose obtained by measurements and by calculations is very satisfying.

Neurons derived from embryonic stem (ES) cells resemble normal neurons in their vulnerability to excitotoxic death

We determined whether embryonic stem (ES) cells could provide a model system for examining neuronal death mediated by glutamate receptors. Although limited evidence indicates that normal neurons can be derived from mouse ES cells, there have been no studies examining pathophysiological responses in mouse ES cell systems. Mouse ES cells, induced down a neural lineage by retinoic acid (RA), were found to have enhanced long-term survival when plated onto a layer of cultured mouse cortical glial cells. In these conditions, the ES cells differentiated into neural cells that appeared normal morphologically and displayed normal features of immunoreactivity when tested for neuron-specific elements. Varying the culture medium generated cultures of mixed neuronal/glial cells or enriched in oligodendrocytes. These cultures were viable for at least four weeks. Real-time PCR analysis of N-methyl-D-aspartate (NMDA) receptor subunits revealed an appropriate age-in-vitro dependent pattern of expression. Neurons derived from ES cells were vulnerable to death induced by a 24-h exposure to the selective glutamate receptor agonists NMDA, kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). This vulnerability to agonist-induced death increased with age in vitro, and related closely to expression of receptor subunits, as it does in cultured primary neurons. Experiments with selective receptor antagonists showed that glutamate receptors mediated the NMDA- and kainate-induced death. Neuronal differentiated ES cells therefore exhibited an excitotoxic response resembling that displayed by central nervous system (CNS) neurons. Thus, ES cells, which are very amenable to genetic manipulation, provide a valid system for studying glutamate receptor-mediated toxicity at the molecular level.

Tooth agenesis: a report of missing molars in two generations

A recent review has suggested that tooth agenesis is becoming more evident in society, though it is not known whether this observation is related to better detection methods and patient awareness or whether there is a real trend towards an increase in prevalence. In this paper we report developmental absence of permanent molars in two generations, and discuss the possible clinical implications of this pattern of tooth agenesis.

Review article: The advent of capsule endoscopy--a not-so-futuristic approach to obscure gastrointestinal bleeding

Capsule endoscopy is a new, wireless, endoscopic examination of the small intestine. To date, two small clinical trials have been reported utilizing capsule endoscopy in patients with obscure gastrointestinal bleeding, and have shown its superiority to push enteroscopy in diagnosing the cause of blood loss. No outcome studies have been reported. This paper proposes a change in practice guidelines for obscure bleeding. It is our opinion that, in the future, with the advent of wireless capsule endoscopy, the evaluation of patients with obscure gastrointestinal bleeding will be very different from the practice of medicine today. We believe that capsule endoscopy will become the first-line method for the evaluation of patients with obscure bleeding, once upper endoscopy and colonoscopy have been shown to be negative. In patients with active bleeding, capsule endoscopy will confirm the small bowel as the site of bleeding, providing a location, or, if the study is negative for the small intestine, may indicate that the bleeding is either colonic or gastric in origin. In a patient with active bleeding within the small intestine, the capsule will guide further evaluation and therapy. A patient with a small bowel tumour detected by capsule endoscopy will proceed directly to laparoscopic surgery. If the site of bleeding is identified in the proximal small bowel and there is no mass, push enteroscopy will be used to re-identify the site and cauterize it. A distal small bowel site will require surgical intervention, coupled with intra-operative enteroscopy. Should the patient be too sick to undergo surgery, medical therapy utilizing hormonal agents will be considered. A colonic site will be evaluated by colonoscopy. In patients with a more occult or intermittent type of bleeding and in those whose upper endoscopies and colonoscopies are negative, capsule endoscopy will be used similarly to identify a bleeding lesion and thereby direct subsequent testing or treatment.

The development of an historical baseline of water balance and environmental flows

This paper has been motivated by a desire to put some numbers beside the label of sustainability as is currently applied to water related issues. Of particular interest is a general estimate of the water balance and environmental flows during the time intervals before Aboriginal arrival, when the land was being managed in an environmentally sustainable manner by the Aboriginals, and most recently following European settlement. This will be considered in an Australia-wide context, because the continent is geographically diverse, being mostly arid desert, with limited areas of fertile soils. Climate variation ranging from a hot tropical north to a cool temperate south will also be discussed. Attention will be given to the major factors that have influenced the water balance, including the extinction of Australian megafauna, the effects of "fire-stick" farming and the clearance of land for European agriculture with its consequences. It is hoped that the findings will increase our understanding of Australian water resources, and promote a greater appreciation of the fragility of this ancient landscape on which we dwell.

Transplacental toxoplasmosis in a reindeer (Rangifer tarandus) fetus

Toxoplasma gondii infection was diagnosed in a full term stillborn reindeer (Rangifer tarandus) fetus. The fetus had encephalitis and placentitis associated with T. gondii. Tissue cysts were identified histologically in sections of brain and tachyzoites were present in placenta and the myocardium. Protozoa in the brain, heart, and placenta stained positively with T. gondii antibodies, but not with Neospora caninum antibodies in an immunohistochemical test. The dam of the fetus had a 1:12,800 titer to T. gondii in the modified agglutination test employing whole tachyzoites and mercaptoethanol. This is the first confirmed report of T. gondii infection in reindeer.

Measurement of analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region with a 22-GeV/c polarized proton beam

The analyzing power for proton-carbon elastic scattering in the Coulomb-nuclear interference region of momentum transfer, 9.0x10(-3)<-t<4.1x10(-2) (GeV/c)(2), was measured with a 21.7 GeV/c polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to nonflip amplitude, r(5), was obtained from the analyzing power to be Rer(5)=0.088+/-0.058 and Imr(5)=-0.161+/-0.226.

Congenital hypothyroidism in Western Australia 1981-1998

OBJECTIVE

Newborn screening for congenital hypothyroidism began in Western Australia in 1981. We describe the epidemiology, including trends over time.

METHODOLOGY

Population-based registers and databases were used to identify cases of congenital hypothyroidism in 1981-1998 (n = 126), a random sample of controls (n = 1260), and descriptive data on cases and controls. The prevalence of congenital hypothyroidism per 10 000 live births was calculated, and a case-control analysis conducted.

RESULTS

The prevalence of congenital hypothyroidism was 1.74 per 10 000 in the period 1981-1987, compared with 3.54 per 10 000 between 1988 and 1998. Infants identified with congenital hypothyroidism were significantly more likely to have other birth defects (particularly heart defects), be female, have a birthweight heavier than 4500 g, and be born either preterm or after 41 weeks gestation. No cases had cerebral palsy or intellectual disability.

CONCLUSIONS

Population-based registers and linked databases can provide very useful information for evaluating screening programmes, and extending our knowledge of the epidemiology of congenital hypothyroidism.

A pilot study of recombinant insulin-like growth factor-1 in seven multiple sderosis patients

The purpose of this open-label, crossover study was to determine the safety and efficacy of recombinant insulin-like growth factor-1 (rhIGF-1) using magnetic resonance imaging (MRI) and clinical measures of disease activity in seven multiple sderosis (MS) patients. Monthly clinical and MPI examinations were performed during a 24-week baseline and a 24-week treatment period with rhIGF-1. The primary outcome measure was contrast enhancing lesion (CEL) frequency on treatment compared to baseline. Secondary outcome measures included dinical and MRI measures of disease activity including: white matter lesion load (WMLL), magnetization transfer ratio (MTR), T1-Hypointensity volume, cervical spine cross-sectional area and proton magnetic resonance spectroscopic (MRS) imaging for determining regional metabolite ratios. rhIGF-1 (Cephalon) was administered at a dose of 50 mg subcutaneously twice a day for 6 months. rhIGF-1 was safe and well tolerated with no severe adverse reactions. There was no significant difference between baseline and treatment periods for any MRI or clinical measures of disease activity. Although rhIGF-1 did not alter the course of disease in this small cohort of MS patients, the drug was well tolerated. Further studies using rhIGF-1 alone or in combination with other therapies may be of value because of the proposed mechanism of action of this growth factor on the oligodendrocyte and remyelination.

CD98-mediated links between amino acid transport and beta 1 integrin distribution in polarized columnar epithelia

In non-polarized cells, CD98 has been shown to both influence beta(1) integrins and heterodimerize with LAT-2, which confers amino acid transport capability on the LAT-2/CD98 heterodimer. Since LAT-2 is most heavily expressed in intestine and CD98 associates with the beta(1) integrin splice form selectively found in such epithelia, we investigated the relationship and polarity of these proteins using the intestinal epithelial model Caco2-BBE. CD98 was found to selectively coimmunoprecipitate with both LAT-2 and beta(1) integrin, and, logically, all three proteins were polarized to the same (basolateral) domain. Furthermore, expression of CD98 in polarized epithelia lacking human CD98 (MDCK cells) disrupted beta(1) integrin surface distribution and cytoskeletal architecture, suggesting that CD98 can influence integrin function. Expression of a CD98 mutant lacking the specific residues conferring LAT-2 binding similarly affected cells, confirming that the latter effect was not due to LAT-2 sequestration. Use of CD98 truncation mutants suggest that a 10-amino acid domain located at the putative cytoplasmic tail/transmembrane domain interface was necessary and sufficient to induce the phenotype change. We conclude that the CD98/LAT-2 amino acid transporter is polarized to the same domain on which beta(1) integrin resides. CD98 appears to associate with beta(1) integrin and, in doing so, may influence its function as revealed by disruption of the outside-in signaling that confers cytoskeletal organization. Furthermore, such findings suggest a link between classic transport events and a critical element of barrier function: integrin-mediated influences on cytoskeletal organization.

Metal-organic complexation in the marine environment

We discuss the voltammetric methods that are used to assess metal-organic complexation in seawater. These consist of titration methods using anodic stripping voltammetry (ASV) and cathodic stripping voltammetry competitive ligand experiments (CSV-CLE). These approaches and a kinetic approach using CSV-CLE give similar information on the amount of excess ligand to metal in a sample and the conditional metal ligand stability constant for the excess ligand bound to the metal. CSV-CLE data using different ligands to measure Fe(III) organic complexes are similar. All these methods give conditional stability constants for which the side reaction coefficient for the metal can be corrected but not that for the ligand. Another approach, pseudovoltammetry, provides information on the actual metal-ligand complex(es) in a sample by doing ASV experiments where the deposition potential is varied more negatively in order to destroy the metal-ligand complex. This latter approach gives concentration information on each actual ligand bound to the metal as well as the thermodynamic stability constant of each complex in solution when compared to known metal-ligand complexes. In this case the side reaction coefficients for the metal and ligand are corrected. Thus, this method may not give identical information to the titration methods because the excess ligand in the sample may not be identical to some of the actual ligands binding the metal in the sample.

Dietary biotin intake modulates the pool of free and protein-bound biotin in rat liver

The current studies were undertaken to analyze the relationships among dietary biotin intake, hepatic free biotin and hepatic protein-bound biotin in rats. The biotin status of rats was manipulated through dietary intervention to model moderate biotin deficiency, adequacy, supplementation and pharmacologic biotin supplementation (0, 0.06, 0.6 and 100 mg/kg, respectively). Urinary biotin excretion was directly related to biotin intake, but no difference between biotin-adequate and biotin-supplemented rats was detected. In contrast, plasma biotin was directly and significantly regulated by biotin intake at every intake level. A hepatic free biotin pool was directly demonstrated in these studies, and like plasma, its size was directly related to dietary biotin intake. The relationship between dietary biotin intake and protein-bound biotin was also analyzed. Moderate biotin deficiency markedly decreased the abundance of each biotinylated polypeptide in rat liver. Biotin supplementation did not significantly elevate the abundance of biotinylated pyruvate, propionyl CoA, methylcrotonyl CoA or acetyl CoA carboxylase 1. The abundance of biotinylated acetyl CoA carboxylase 2, however, was significantly higher in biotin-supplemented rats. Pharmacologic biotin intake significantly reduced the abundance of biotinylated propionyl CoA and methylcrotonyl CoA carboxylase. These results indicate the following: 1) moderate biotin deficiency reduces free and protein bound biotin; 2) biotin intakes in rats that mimic the currently recommended daily value (DV) do not result in full protein biotinylation; and 3) pharmacologic supplementation may reduce the abundance of functional carboxylases.