Does fluoride rinsing have an effect on teeth status? Evaluation of preventive dental health activities for the youth of Woudenberg, The Netherlands

Surveys among primary school children of group 8 (mainly 12-year olds) in 1988/1989 and 1995/1996 revealed that the dental status in Woudenberg was worse than in other municipalities in the Eemland region. Therefore, several dental preventive activities were started in Woudenberg for children aged 0-12 years. This included fluoride rinsing and teeth brushing lessons at primary schools. So as to evaluate the effect of these school activities, a new survey was carried out in Woudenberg in 2004. The teeth status (DMF-S value, percentage sound teeth, percentage erosion) was investigated by examination. Information regarding dental hygiene behaviour and participation in teeth brushing lessons was obtained by questionnaire. Teeth status (measured by DMF-S value as well as percentage sound teeth) at rinsing schools in 2004 was significantly better than at the same schools in 1995/1996. Multivariate analyses revealed that fluoride rinsing for at least 3 years (besides educational level of parents) is the most determining factor for teeth status independent of other variables. Pupils who never rinsed with fluoride were almost four times more likely to have caries lesions than pupils who rinsed for at least 3 years. This study strongly indicates that long-term rinsing with fluoride has a positive effect on teeth status.

Targeted disruption of the Cln3 gene provides a mouse model for Batten disease. The Batten Mouse Model Consortium [corrected]

Batten disease, a degenerative neurological disorder with juvenile onset, is the most common form of the neuronal ceroid lipofuscinoses. Mutations in the CLN3 gene cause Batten disease. To facilitate studies of Batten disease pathogenesis and treatment, a murine model was created by targeted disruption of the Cln3 gene. Mice homozygous for the disrupted Cln3 allele had a neuronal storage disorder resembling that seen in Batten disease patients: there was widespread and progressive intracellular accumulation of autofluorescent material that by EM displayed a multilamellar rectilinear/fingerprint appearance. Inclusions contained subunit c of mitochondrial ATP synthase. Mutant animals also showed neuropathological abnormalities with loss of certain cortical interneurons and hypertrophy of many interneuron populations in the hippocampus. Finally, as is true in Batten disease patients, there was increased activity in the brain of the lysosomal protease Cln2/TPP-1. Our findings are evidence that the Cln3-deficient mouse provides a valuable model for studying Batten disease.

A murine model for juvenile NCL: gene targeting of mouse Cln3

JNCL is a neurodegenerative disease of childhood caused by mutations in the CLN3 gene. A mouse model for JNCL was created by disrupting exons 1-6 of Cln3, resulting in a null allele. Cln3 null mice appear clinically normal at 5 months of age; however, like JNCL patients, they exhibit intracellular accumulation of autofluorescent material. A second approach will generate mice in which exons 7 and 8 of Cln3 are deleted, mimicking the common mutation in JNCL patients.

Rapid detection of the major deletion in the Batten disease gene CLN3 by allele specific PCR

The recent isolation of the CLN3 gene involved in Batten disease (juvenile neuronal ceroid lipofuscinosis) creates possibilities for direct detection of mutations which can confirm or indicate the clinical diagnosis of Batten disease. We have designed a rapid and reliable allele specific PCR test for the detection of the major deletion, which can be used in carrier diagnosis, presymptomatic diagnosis, and prenatal diagnosis.

Spectrum of mutations in the Batten disease gene, CLN3

Batten disease (juvenile-onset neuronal ceroid lipofuscinosis [JNCL]) is an autosomal recessive condition characterized by accumulation of lipopigments (lipofuscin and ceroid) in neurons and other cell types. The Batten disease gene, CLN3, was recently isolated, and four disease-causing mutations were identified, including a 1.02-kb deletion that is present in the majority of patients (The International Batten Disease Consortium 1995). One hundred eighty-eight unrelated patients with JNCL were screened in this study to determine how many disease chromosomes carried the 1.02-kb deletion and how many carried other mutations in CLN3. One hundred thirty-nine patients (74%) were found to have the 1.02-kb deletion on both chromosomes, whereas 49 patients (41 heterozygous for the 1.02-kb deletion) had mutations other than the 1.02-kb deletion. SSCP analysis and direct sequencing were used to screen for new mutations in these individuals. Nineteen novel mutations were found: six missense mutations, five nonsense mutations, three small deletions, three small insertions, one intronic mutation, and one splice-site mutation. This report brings the total number of disease-associated mutations in CLN3 to 23. All patients homozygous for mutations predicted to give rise to truncated proteins were found to have classical JNCL. However, a proportion of the patients (n = 4) who were compound heterozygotes for a missense mutation and the 1.02-kb deletion were found to display an atypical phenotype that was dominated by visual failure rather than by severe neurodegeneration. All missense mutations were found to affect residues conserved between the human protein and homologues in diverse species.

Genomic structure and complete nucleotide sequence of the Batten disease gene, CLN3

We recently cloned a cDNA for CLN3, the gene for juvenile-onset neuronal ceroid lipofuscinosis or Batten disease. To resolve the genomic organization we used a cosmid clone containing CLN3 to sequence the entire gene in addition to 1.1 kb 5' of the start of the published CLN3 cDNA and 0.3 kb 3' to the polyadenylation site. CLN3 is organized into at least 15 exons spanning 15 kb and ranging from 47 to 356 bp. The 14 introns vary from 80 to 4227 bp, and all exon/intron junction sequences conform to the GT/AG rule. Numerous repetitive Alu elements are present within the introns and 5'- and 3'-untranslated regions. The 5' region of the CLN3 gene contains several potential transcription regulatory elements but no consensus TATA-1 box was identified. CLN3 is homologous to 27 deposited human ESTs, and sequence comparisons suggest alternative splicing of the gene and the existence of transcribed sequences upstream to the start of the published CLN3 cDNA.

Cross-species homology of the CLN3 gene

A murine cDNA clone was isolated by screening a mouse cDNA library with the human CLN3 cDNA. Sequence analysis indicates that the corresponding CLN3 proteins are highly homologous. We have compared these with recently identified CLN3 sequences from the dog, the nematode C. elegans, and baker's yeast S. cerevisiae. The CLN3 protein is remarkably conserved across eukaryotic species. Several protein modification sites which may be crucial for the function of the protein are conserved.

YAC and cosmid contigs spanning the Batten disease (CLN3) region at 16p12.1-p11.2

A yeast artificial chromosome (YAC) contig has been constructed in 16p12.1-p11.2 that encompasses three loci (D16S288, D16S299, and D16S298) closely linked to the gene causing Batten disease or juvenile-onset neuronal ceroid lipofuscinosis (CLN3). The physical map has been ordered using 42 sequence tagged sites. Four genes, interleukin-4 receptor (IL4R), phenol-preferring phenol sulfotransferase (STP), monoamine-preferring phenol sulfotransferase (STM), and sialophorin (SPN), have been mapped to the YAC contig. A partial genomic restriction map has been constructed to confirm the order and distances between D16S298, predicted to be the locus closest to CLN3. The overlapping genomic clones are a valuable resource for cloning the Batten gene (CLN3) and other genes in the region.

Application of chromosome 16 markers in the differential diagnosis of neuronal ceroid-lipofuscinosis

Accurate diagnosis of neuronal ceroid lipofuscinosis (NCL) is important for a correct prognosis of the disease and for genetic counseling. Up to now, no direct diagnostic test has been available for NCL. The clinical diagnosis is made on the basis of symptoms, neurophysiological, neuroradiological, and specific lipopigment pattern data. Recent advances in the genetics of NCL have enabled us to use polymorphic DNA markers linked to the CLN1 and CLN3 loci as a tool in the differential diagnosis of NCL. We have applied genetic analysis with polymorphic DNA markers flanking the CLN3 gene on chromosome 16 to two consanguineous families in which NCL occurs. In the first family, which is of Turkish extraction, two patients suffering from a protracted form of juvenile NCL previously had been diagnosed with juvenile NCL. Haplotypes from this family indicate that the patients and their healthy sibling are haplo-identical, suggesting that this protracted form of juvenile NCL is not linked to the CLN3 locus. In the second family, which is of Moroccan origin, one patient suffers from the early juvenile variant of NCL (Lake-Cavanagh). In this family, the patient and one of the healthy siblings have identical haplotypes, excluding linkage of early juvenile NCL to the CLN3 locus on 16p12.1-11.2. Therefore, these cases from different populations demonstrate that haplotype analysis can be used as an additional method to exclude the diagnosis of juvenile NCL.

Refined localization of the Batten disease gene (CLN3) by haplotype and linkage disequilibrium mapping to D16S288-D16S383 and exclusion from this region of a variant form of Batten disease with granular osmiophilic deposits

Haplotype analysis in a collaborative collection of 143 families with juvenile-onset neuronal ceroid lipofuscinosis (JNCL) or Batten (Spielmeyer-Vogt-Sjögren) disease has permitted refined localization of the disease gene, CLN3, which was assigned to chromosome 16 in 1989. Recombination events in four maternal meioses delimit new flanking genetic markers for CLN3 which localize the gene to the chromosome interval 16p12.1-11.2 between microsatellite markers D16S288 and D16S383. This narrows the position of CLN3 to a region of 2.1 cM, a significant reduction from the previous best interval. Using haplotypes, analysis of the strong linkage disequilibrium that exists between genetic markers within the D16S288-D16S383 interval and CLN3 shows that CLN3 is in closest proximity to loci D16S299 and D16S298. Analysis of markers across the D16S288-D16S383 region in four families with a variant form of JNCL characterized histologically by cytosomal granular osmiophilic deposits (GROD) has excluded linkage of the gene locus to the CLN3 region of chromosome 16, suggesting that JNCL with GROD is not an allelic form of JNCL.

Carrier detection of Batten disease (juvenile neuronal ceroid-lipofuscinosis)

Batten disease, or the juvenile form of neuronal ceroid lipofuscinosis, is an autosomal recessive neurodegenerative disorder manifesting with progressive blindness, seizures, and dementia, leading to an early death. The CLN3 locus which is involved in Batten disease had been localized to chromosome 16p11.2. Linkage disequilibrium has been observed between CLN3 and polymorphic microsatellite markers D16S288, D16S299, and D16S298, making carrier detection and prenatal diagnosis by haplotype analysis possible. For the purpose of carrier detection, haplotypes from Dutch Batten patients and their families were constructed. Most patients share the same D16S298 allele, suggesting the presence of a founder effect in the Dutch population. In a large inbred Dutch family, in which Batten disease occurs with high frequency, haplotype analysis has been carried out with high accuracy for carrier detection.

Isolation of genes from the Batten candidate region using exon amplification. Batten Disease Consortium

In order to identify genes originating from the Batten disease candidate region, we have used the technique of exon amplification to identify transcribed sequences. This procedure produces trapped exon clones, which can represent single exons or multiple exons spliced together and is an efficient method for obtaining probes for physical mapping and for screening cDNA libraries. The source of DNA for these experiments was a collection of chromosome 16 cosmid contigs isolated by the direct subcloning of region-specific yeast artificial chromosomes (YACs) and hybridization of inter-alu PCR products from these YACs to the flow-sorted Los Alamos chromosome 16 cosmid library. We are now using the resulting exon probes to screen retina and brain cDNA libraries for candidate JNCL genes.

Batten disease gene, CLN3: linkage disequilibrium mapping in the Finnish population, and analysis of European haplotypes

The gene for Batten disease (juvenile-onset neuronal ceroid lipofuscinosis, or Spielmeyer-Sjögren disease), CLN3, maps to 16p11.2-12.1. Four microsatellite markers--D16S288, D16S299, D16S298, and SPN--are in strong linkage disequilibrium with CLN3 in 142 families from 16 different countries. These markers span a candidate region of approximately 2.1 cM. CLN3 is most prevalent in northern European populations and is especially enriched in the isolated Finnish population, with an incidence of 1:21,000. Linkage disequilibrium mapping was applied to further refine the localization of CLN3 in 27 Finnish families by using linkage disequilibrium data and information about the population history of Finland to estimate the distance of the closest markers from CLN3. CLN3 is predicted to lie 8.8 kb (range 6.3-13.8 kb) from D16S298 and 165.4 kb (132.4-218.1 kb) from D16S299. Enrichment of allele "6" at D16S298 (on 96% of Finnish and 92% of European CLN3 chromosomes) provides strong evidence that the same major mutation is responsible for Batten disease in Finland as in most other European countries and that it is therefore not a Finnish mutation. Genealogical studies show that Batten disease is widespread throughout the densely populated regions of Finland. The ancestors of two Finnish patients carrying rare alleles "3" and "5" at D16S298 in heterozygous form originate from the southwestern coast of Finland, and these probably represent other foreign mutations. Analysis of the number and distribution of CLN3 haplotypes from 12 European countries provides evidence that more than one mutation has arisen in Europe.

Chromosome 16 microdeletion in a patient with juvenile neuronal ceroid lipofuscinosis (Batten disease)

The gene that is involved in juvenile neuronal ceroid lipofuscinosis (JNCL), or Batten disease--CLN3--has been localized to 16p12, and the mutation shows a strong association with alleles of microsatellite markers D16S298, D16S299, and D16S288. Recently, haplotype analysis of a Batten patient from a consanguineous relationship indicated homozygosity for a D16S298 null allele. PCR analysis with different primers on DNA from the patient and his family suggests the presence of a cytogenetically undetectable deletion, which was confirmed by Southern blot analysis. The microdeletion is embedded in a region containing chromosome 16-specific repeated sequences. However, putative candidates for CLN3, members of the highly homologous sulfotransferase gene family, which are also present in this region in several copies, were not deleted in the patient. If the microdeletion in this patient is responsible for Batten disease, then we conclude that the sulfotransferase genes are probably not involved in JNCL. By use of markers and probes flanking D16S298, the maximum size of the microdeletion was determined to be approximately 29 kb. The microdeletion may affect the CLN3 gene, which is expected to be in close proximity to D16S298.

Genetic mapping of the Batten disease locus (CLN3) to the interval D16S288-D16S383 by analysis of haplotypes and allelic association

CLN3, the gene for juvenile-onset neuronal ceroid lipofuscinosis (JNCL) or Batten disease, has been localized by genetic linkage analysis to chromosome 16p between loci D16S297 and D16S57. We have now further refined the localization of CLN3 by haplotype analysis using two new microsatellite markers from loci D16S383 and SPN in the D16S297-D16S57 interval on a larger collaborative family resource consisting of 142 JNCL pedigrees. Crossover events in 3 maternal meioses define new flanking markers for CLN3 and localize the gene to the interval at 16p12.1-p11.2 between D16S288 and D16S383, which corresponds to a genetic distance of 2.1 cM. Within this interval 4 microsatellite loci are in strong linkage disequilibrium with CLN3, and extended haplotype analysis of the associated alleles indicates that CLN3 is in closest proximity to loci D16S299 and D16S298.

Selenium status and cardiovascular risk factors in healthy Dutch subjects

To provide further insight into the possible role of selenium in cardiovascular disease, we examined the relationship between cardiovascular risk factors, some nutritional parameters, and short- and long-term selenium status. A total of 82 healthy Dutch volunteers, 59 men and 23 women, aged 40-75 years, were studied. Means and standard deviations of selenium parameters were: plasma selenium 106.4 +/- 23.7 micrograms/L, erythrocyte selenium 0.59 +/- 0.19 microgram/g Hb, toenail selenium 0.78 +/- 0.17 ppm, and erythrocyte glutathione peroxidase activity 28.0 +/- 8.1 U/g Hb. No association was found between selenium status and gender, age, serum total-, LDL-, and HDL-cholesterol, systolic and diastolic blood pressure, alcohol intake, and body mass index. A significantly lower plasma selenium level was observed among smokers compared to nonsmokers (101.0 micrograms/L, SE = 3.9 vs 112.0 micrograms/L, SE = 3.6, p = 0.04). A significant negative association was found between erythrocyte selenium and serum levels of vitamin A and ferritin. No relevant relationship was observed between selenium status and serum fatty acid composition, vitamin E, vitamin B6, and iron. Apart from an association between smoking and short-term selenium status, we found no indications that a possible effect of selenium on cardiovascular disease may operate through the known risk factors.

Serum cobalamins and cobalamin-binding proteins during total parenteral nutrition

Levels of serum cobalamin and both saturated and unsaturated serum cobalamin-binding proteins (transcobalamin II and R-binders) were determined prospectively in 43 patients before and after 2 weeks of total parenteral nutrition (TPN). Nine patients showed subnormal serum levels of cobalamin but none of them had clinical signs of cobalamin deficiency. Serum cobalamin levels significantly declined after 2 weeks of TPN as did both saturated and unsaturated R-binder levels whereas transcobalamin II levels remained constant. Since cobalamin in serum is entirely bound to proteins, of which R-binders comprise 80-90%, the changes in R-binder levels will markedly influence serum cobalamin levels, in fact they adequately explain the short time fluctuations of serum cobalamin levels observed. It is argued that the changes in serum cobalamin levels may reflect a changed distribution of cobalamins over the various body compartments rather than decreased or increased body stores. Moreover, only cobalamin bound to transcobalamin II is delivered to the tissues. Therefore, serum cobalamin levels alone may inadequately reflect cobalamin availability in patients receiving TPN.

A new selective medium for the culture of clostridia from human faeces

A new selective medium, sulphite-polymixin-milk (SPM) agar, for the isolation of clostridia from faeces is described. This medium contains whole cow's milk, which favours the growth of clostridia over that of Bacteroides and Bifidobacterium spp., and only small amounts of colistin (10 micrograms/ml) for suppressing growth of coliforms. The alkaline end-products of clostridia give rise to yellow colonies on a red background which are easy to distinguish from the red colonies of other not completely inhibited bacteria. The medium is suitable for isolation of many clostridia species. Comparisons were made between SPM and several other media for recovery of clostridia. The detection limit on SPM agar was more than 10(3) below that on Reinforced Clostridia Agar (Oxoid CM101).