Hypochondriasis: the role of fear-confirming reasoning

We investigated whether hypochondriacal patients are prone to selectively search for danger-confirming information when asked to judge the validity of conditional rules in the context of general and health threats. Therefore, hypochodtriacal patients (n = 27) and a healthy control group (n = 27) were presented with modified Wason Selection Tasks (WSTs) pertaining to general and health threats. The WSTs contained safety rules (If P then safe) and danger rules (If P then danger). Subjects adopted a verificationistic strategy in case of danger rules and tended to look for falsifications in case of safety rules. This danger-confirming reasoning pattern was similar for both types of contexts and not particularly pronounced in hypochondriacal persons. These findings argue against the idea that such a reasoning pattern directly causes hypochondriasis. Yet, in the presence of anxiogenic (hypochondriasis related) convictions such danger-confirming reasoning pattern logically serves to maintain or even enhance hypochondriacal complaints.

Contig maps and genomic sequencing identify candidate genes in the usher 1C locus

Usher syndrome 1C (USH1C) is a congenital condition manifesting profound hearing loss, the absence of vestibular function, and eventual retinal degeneration. The USH1C locus has been mapped genetically to a 2- to 3-cM interval in 11p14-15.1 between D11S899 and D11S861. In an effort to identify the USH1C disease gene we have isolated the region between these markers in yeast artificial chromosomes (YACs) using a combination of STS content mapping and Alu-PCR hybridization. The YAC contig is approximately 3.5 Mb and has located several other loci within this interval, resulting in the order CEN-LDHA-SAA1-TPH-D11S1310-(D11S1888/KCNC1 )-MYOD1-D11S902D11S921-D11S 1890-TEL. Subsequent haplotyping and homozygosity analysis refined the location of the disease gene to a 400-kb interval between D11S902 and D11S1890 with all affected individuals being homozygous for the internal marker D11S921. To facilitate gene identification, the critical region has been converted into P1 artificial chromosome (PAC) clones using sequence-tagged sites (STSs) mapped to the YAC contig, Alu-PCR products generated from the YACs, and PAC end probes. A contig of >50 PAC clones has been assembled between D11S1310 and D11S1890, confirming the order of markers used in haplotyping. Three PAC clones representing nearly two-thirds of the USH1C critical region have been sequenced. PowerBLAST analysis identified six clusters of expressed sequence tags (ESTs), two known genes (BIR, SUR1) mapped previously to this region, and a previously characterized but unmapped gene NEFA (DNA binding/EF hand/acidic amino-acid-rich). GRAIL analysis identified 11 CpG islands and 73 exons of excellent quality. These data allowed the construction of a transcription map for the USH1C critical region, consisting of three known genes and six or more novel transcripts. Based on their map location, these loci represent candidate disease loci for USH1C. The NEFA gene was assessed as the USH1C locus by the sequencing of an amplified NEFA cDNA from an USH1C patient; however, no mutations were detected.

High-resolution mapping and transcript identification at the progressive epilepsy with mental retardation locus on chromosome 8p

Progressive epilepsy with mental retardation (EPMR) is an autosomal recessive central nervous system disorder characterized by childhood onset epilepsy and subsequent mental retardation. The locus for EPMR has been mapped to human chromosome 8p23. We recently reported the construction of a YAC contig across the 4 centimorgan minimum genetic region that harbors the disease locus. We now report further delineation of the critical region to <700 kb. Our mapping strategy relied on the identification of nine novel microsatellite markers and the construction of a complete BAC contig across the critical region. Several partial gene sequences have been identified from the region and are being analyzed as candidate genes for EPMR.

Transfer of small YACs to E. coli as large circular plasmids

We have designed a YAC circularization vector, pCIRC3, allowing enrichment of the YAC DNA by exonuclease digestion of the linear yeast chromosomes. Due to the presence of P1 replicon sequences in this vector, the circular YACs would replicate as PACs in Escherischia coli.

A 2.8-Mb clone contig of the multiple endocrine neoplasia type 1 (MEN1) region at 11q13

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder that results in parathyroid, anterior pituitary, and pancreatic and duodenal endocrine tumors in affected individuals. The MEN1 locus is tightly linked to the marker PYGM on chromosome 11q13, and linkage analysis has placed the MEN1 gene within a 2-Mb interval flanked by D11S1883 and D11S449. As a step toward cloning the MEN1 gene, we have constructed a 2.8-Mb clone contig consisting of YAC and bacterial clones (PAC, BAC, and P1) for the D11S480 to D11S913 region. The bacterial clones alone represent nearly all of the 2.8-Mb contig. The contig was assembled based on a high-density STS-content analysis of 79 genomic clones (YAC, PAC, BAC, and P1) with 118 STSs. The STSs included 22 polymorphic markers and 20 transcripts, with the remainder primarily derived from the end sequences of the genomic clones. An independent cosmid contig for the 1-Mb PYGM-SEA region was also generated. Support for correctness of the 2.8-Mb contig map comes from an independent ordering of the clones by fiber-FISH. This sequence-ready contig will be a useful resource for positional cloning of MEN1 and other disease genes whose loci fall within this region.

Conditional reasoning and phobic fear: evidence for a fear-confirming reasoning pattern

In two experiments we explored the role of subjects' reasoning performance in the persistence of phobic fear. More specifically, we investigated whether (phobic) subjects are prone to selectively search for danger-confirming information when asked to judge the validity of conditional rules in the context of general and phobic threats. In both experiments, participants were presented with Wason Selection Tasks (WST) pertaining to general and phobic threats. The WSTs contained safety rules (if P then no danger) and danger rules (if P then danger). In Experiment 1 participants were high (n = 20) and low (n = 20) spider fearful students, whereas in Experiment 2 participants were untreated (n = 38) and treated (n = 27) spider phobic women and a group of non-fearful controls (n = 27). Both experiments showed that in the context of general threat, subjects predominantly rely on confirming information regarding danger rules and on falsifying information regarding safety rules. This reasoning strategy was not particularly pronounced in high fear or phobic subjects. However, only clinically diagnosed spider phobics displayed a similar reasoning strategy in the context of phobia-relevant threats. Thus, the present data seem to suggest that the mere perception of threat is already sufficient to activate a danger-confirming reasoning strategy and in case of phobic threats such a reasoning pattern logically serves to maintain or even enhance phobic fears.

A sequence-ready high-resolution physical map of the best macular dystrophy gene region in 11q12-q13

Best disease, an autosomal dominant inherited macular degenerative disorder, was previously localized between D11S1765 and UGB (uteroglobin) in 11q13 by genetic linkage analysis. Since this region was found to be refractory to cloning in YAC (yeast artificial chromosome)-based vectors, a P1 artificial chromosome (PAC) contig was assembled. Gridded PAC libraries representing a 16-fold genome equivalent were screened by hybridization using PCR products representing STSs derived from YAC end sequences, markers binned to 11q13, and PAC-derived insert ends. A highly marker dense approximately 1.7-Mb PAC contig that encompassed the disease gene region was constructed, allowing us to order accurately the markers throughout the region and to provide the most precise estimate of its physical size. Using this contig, thus far we have mapped seven anonymous ESTs and five known genes into this region. This high-resolution physical map will facilitate the isolation of polymorphic markers for refinement of the disease gene region, as well as the identification of candidate genes by exon trapping, cDNA selection, and gene prediction from PAC-derived genomic sequence.

BAC and PAC contigs covering 3.5 Mb of the Down syndrome congenital heart disease region between D21S55 and MX1 on chromosome 21

Chromosome 21 is a model for the study of human chromosomal aneuploidy, and the construction of its physical and transcriptional maps is a necessary step in understanding the molecular basis of aneuploidy-dependent phenotypes. To identify the gene(s) responsible for Down syndrome congenital heart disease (DS-CHD), we constructed a physical map of the D21S55 to MX1 region. A bacterial artificial chromosome (BAC) library was screened using several YACs spanning the interval, and a P1-derived artificial chromosome (PAC) library was screened using radiolabeled STS PCR products and whole BACs in gap-filling initiatives. FISH confirmed the location of all BAC and PAC clones to 21q22.2-q22.3. Overlaps were established using clone-to-clone Southerns and 24 new STSs, generated from the direct sequencing of BAC and PAC ends, along with 35 preexisting STSs. Approximately 3.5 Mb of the 4- to 5-Mb D21S55 to MX1 interval is covered in 85 BACs and 24 PACs, representing fourfold coverage within the contigs. These BAC and PAC contigs are valuable reagents for isolating the genes for DS-CHD.

Analysis of the 5' sequence, genomic structure, and alternative splicing of the presenilin-1 gene (PSEN1) associated with early onset Alzheimer disease

Mutations in the human presenilin genes (PSEN1 and PSEN2) are associated with early onset familial Alzheimer disease. The presenilin genes encode integral membrane proteins with similar structures, which suggests that they may have closely related, but as yet unknown functions. Analysis of the 5' upstream sequence and the structure of the PSEN1 gene reveals that the 5' sequence contains multiple putative transcription regulatory elements including clusters of STAT elements involved in transcriptional activation in response to signal transduction. The first four exons contain untranslated sequences, with Exons 1 and 2 representing alternate initial transcription sites. The function of these alternate initial exons is unclear. Exon 4 bears the first ATG sequence. The last 12 bp of Exon 4 is used as an alternative splice donor site. Exon 9 is alternately spliced in leukocytes, but not in most other tissues. Splicing of Exon 9 is predicted to cause significant structural changes to the protein. The majority of transcripts expressed in most tissues are polyadenylated 1127 bp from the TAG stop codon in Exon 13. A small proportion of transcripts contain the same 5'UTR and ORF but are polyadenylated 4435 bp from the stop codon. The longer polyadenylated transcripts contain three additional palindromes and at least one additional stem-loop structure with stabilities greater than -16 kcal/mol.

The gene cluster containing the LCAT gene is conserved between human and pig

A pooled DNA probe from P1 artificial chromosome clones (PACs) containing the human lecithin:cholesterol acyl transferase (LCAT) gene cluster was used in fluorescence in situ hybridization (FISH) experiments assigning the genes to pig chromosome 6p13. In addition, probes derived from the coding regions in the human gene cluster were used in long range mapping experiments to show that the overall structures of the human and porcine LCAT gene clusters are identical. Both the linear order and the close physical distance of five apparently unrelated genes have been maintained throughout 90 million years of divergent evolution between human and pig. The extremely dense clustering of the genes in the LCAT gene cluster suggests that this gene organization has biological significance. The conservation of the gene cluster between human and pig supports this suggestion.

Disgust and spider phobia

Twenty-four women with spider phobia and 45 nonphobic women completed the Disgust Questionnaire (DQ; P. Rozin, A. E. Fallon, & R. Mandell, 1984) and the Spider Phobia Questionnaire (SPQ; R. Klorman, T. C. Weerts, J. E. Hastings, B. G. Melamed, & P. J. Lang, 1974). Participants also underwent behavioral tests concerning disgust sensitivity and fear of spiders. Spider phobic women showed stronger disgust sensitivity than nonphobic women, and spiders were found to have a disgust-evoking status that was related to participants' fear of spiders. The relationship between DQ and SPQ was independent of neuroticism and introversion. DQ scores were not associated with a global measure of phobic complaints (i.e., Fear Questionnaire; I. M. Marks & A. Mathews, 1979). Results are consistent with a disease-avoidance model of spider phobia (G. Matchett & G. C. L. Davey, 1991), which emphasizes the role of disgust in spider phobia.

UCS inflation and human aversive autonomic conditioning

Fifty students participated in a differential conditioning paradigm. In the first part of the experiment, one neutral slide (CS+) was paired with a tone (UCS) and another neutral slide (CS-) was never followed by a tone. During the subsequent inflation phase, unsignalled UCSs gradually increased in strength for the inflation group while they were kept constant for the control group. During extinction trials, the inflation group initially showed relatively stronger UCS expectancies on the CS+ trials than the control group. In contrast to what was predicted, the UCS inflation procedure did not result in stronger conditioning effects of the skin conductance response compared to the control procedure. The effectiveness of the UCS inflation procedure was not related to trait anxiety.

The structural organization of the human skeletal muscle ryanodine receptor (RYR1) gene

The RYR1 gene encoding the Ca2+ release channel of human skeletal muscle sarcoplasmic reticulum has been cloned and exon/intron boundaries have been determined, together with a minimum of 30 bp of intron sequence flanking each splice junction. The gene contains 106 exons, of which two are alternatively spliced. The length of the gene, determined by the alignment of 16 genomic phage clones, a cosmid clone, and several long polymerase chain reaction products, is approximately 160 kb. Exons range from 15 to 813 bp, while introns range from 85 to about 16,000 bp. Analysis of the gene has confirmed published errors in the human RYR1 cDNA and confirmed the structure of two alternatively spliced exons. The numbering of the nucleotides comprising the RYR1 cDNA and the numbering of amino acids encoded by them were corrected to account for these earlier errors and omissions. Analysis of 2.4 kb of the 5' upstream sequence indicated the presence of a CCAAT box and several Sp1 binding sites between nucleotides -200 and -60 bp, flanking the proposed transcription start site at -130 bp. Several other potential transcription factor binding sites were identified throughout the 5' sequence. Knowledge of the structure of the RYR1 gene will provide an invaluable resource for the discovery of mutations in the gene that are causal of human malignant hyperthermia and central core disease.

Identification of three new microsatellite markers in the spinocerebellar ataxia type 2 (SCA2) region and 1.2 Mb physical map

Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease recently mapped to chromosome 12q close to the locus D12S84 by genetic linkage analysis. To generate additional genetic markers in the SCA2 region, we constructed a physical map of the region using yeast artificial chomosome (YAC), P1 artificial chromosome (PAC) and cosmid clones. The physical map was found to agree well with the genetic map. Three novel microsatellite markers were isolated and physically mapped. A novel approach to isolate CAG repeats directly from YAC DNAs is described.

An integrated map with cosmid/PAC contigs of a 4-Mb Down syndrome critical region

The major phenotypic features of Down syndrome have been correlated with partial trisomies of chromosome 21, allowing us to define the candidate gene region to a 4-Mb segment on the 21q22.2 band. We present here a high-resolution physical map with megabase-sized cosmid/PAC contigs. This ordered clone library has provided unique material for the integration of a variety of mappable objects, including exons, cDNAs, restriction sites, etc. Furthermore, our results have exemplified a strategy for the completion of the chromosome 21 map to sequencing.

Isolation of a cosmid sublibrary for a region of chromosome 12 frequently amplified in human cancers using a complex chromosome microdissection probe

Chromosome-specific cosmid libraries are an extremely useful resource for positional cloning projects. Once a particular region of interest has been identified, it would be of value to have an approach for isolating chromosome band-specific cosmids that could be assembled into a sublibrary for rapid screening. We constructed a region-specific sublibrary of 700 cosmids by screening a chromosome 12-specific cosmid library with a complex probe generated by degenerate oligonucleotide-primed PCR of a microdissected homogeneously staining region containing sequences amplified from chromosome 12q13-q15. Based on fluorescence in situ hybridization, approximately 60% of the cosmids in the sublibrary were derived from the microdissected region. To demonstrate further the utility of this sublibrary, a 150-kb contig containing the SAS and CDK4 genes was constructed, as well as several additional contigs between CDK4 and MDM2. This study demonstrates the possibility of utilizing probes generated by microdissection for assembling band-specific sublibraries that are amenable to rapid screening with multiple markers.

The placebo effect in pain reduction: the influence of conditioning experiences and response expectancies

We investigated the role of conditioning experiences and response expectancies in the generation of placebo effects. On 3 sequential days (Test 1, Experimental Session, Test 2), 66 female undergraduates were presented with a series of pain stimuli. For the experimental group, placebo administration (analgesic cream) was paired with a decrease in the painful stimulus. Two control groups were used to explore the relative contributions of verbally induced expectancies and contingent unconditional stimulus experiences per se. The results show that placebo-induced pain reduction can he obtained as a result or a conditioning procedure, independent of verbally induced expectancies. Mere verbal persuasion was not sufficient to elicit placebo-induced pain reduction. Irrespective of the experimental manipulations, the placebo effect was related to both reduced pain expectations and reduced fear of pain. Although conditioned placebo responses were evident at the subjective level, no placebo effects emerged at the physiological level.

Isolation of YAC insert sequences by representational difference analysis

We present a method for the isolation of YAC insert sequences by representational difference analysis (RDA). To achieve maximal representation of the sequences, the amplicons were generated from a Mbol digestion product. RDA was performed using a 970 kb insert YAC clone. After two rounds of re-association and selective amplification 92% of the difference product represented sequences derived from the YAC insert. Twenty insert-specific sequence-tagged sites were readily defined. The difference product was also successfully used to isolate microsatellite markers, to identify clones from a human PAC library and as a chromosome painting probe in fluorescence in situ hybridization.

An integrated high-resolution physical map of the DPC/BRCA2 region at chromosome 13q12

We identified a homozygous deletion in a pancreatic carcinoma (DPC) that localized to a 1-cM region at chromosome 13q12.3, which lay within the 6-cM locus of familial breast cancer susceptibility (BRCA-2). Here we present a physical map of the region, consisting of YAC, PAC, and cosmid contigs. The YAC contig comprises 16 clones that together span the entire BRCA2 region. The PAC contig comprises 22 clones that together span the DPC region. Seventy cosmid clones were localized within and near the DPC region. Thirty-five sequence-tagged sites were defined and localized within the map. The map indicates the size of the DPC region to be near 250 kb, and provides mapped and cloned resources for the search for the putative tumor suppressor gene(s) in the region.

The organization of the human immunoglobulin lambda gene locus

To elucidate the complex structure of the human immunoglobulin lambda gene locus, a 1020-kb contig was constructed using 184 cosmid clones and one bacterial artificial chromosome (BAC) clone. A high-resolution physical map of this contig revealed that the entire lambda gene locus is 911 kb in length. It contains seven constant region (C lambda) gene segments and 69 unique EcoRI-HindIII segments that hybridize to variable region gene (V lambda) probes. The VpreB gene, BCRL4, and gamma-glutamyl transpeptidase gene (GGT)-like sequences are also located within the lambda gene locus. Hybridization analysis suggested that the lambda gene locus has undergone extensive amplification events in evolution.

A 405-kb cosmid contig and HindIII restriction map of the progressive myoclonus epilepsy type 1 (EPM1) candidate region in 21q22.3

As a step toward identifying the molecular defect in patients afflicted with progressive myoclonus epilepsy type 1 (EPM1), we have assembled a cosmid contig of the candidate EPM1 region in 21q22.3. The contig constitutes a collection of 87 different cosmids spanning 405 kb based on a derived HindIII restriction map. Potential CpG-rich islands have been identified based on the restriction map generated from eight different rare-cutting enzymes. This contig contains the genetic material required for the isolation of expressed sequences and the identification of the gene defective in EPM1 and possibly other disorders mapping to this region.

Exposure therapy outcome in spider phobics: effects of monitoring and blunting coping styles

The present study examined whether monitoring (i.e. seeking out threat-related information) and blunting (i.e., avoiding threat-related information) coping styles affect therapy outcome. The sample consisted of 36 spider phobics who underwent one 2.5 hr session of exposure in vivo. Monitoring and blunting were assessed with the Miller Behavioural Style Scale (MBSS) at two points in time: before and after (i.e. at 2 years follow-up) treatment. It was found that coping styles did not change dramatically over a 2-year period. Furthermore, pre-treatment and follow-up coping style scores essentially produced the same results: monitoring was associated with less favourable therapy outcome, whereas blunting was related to better treatment results.

Covariation bias in phobic women: the relationship between a priori expectancy, on-line expectancy, autonomic responding, and a posteriori contingency judgment

Thirty-eight people with spider phobias (19 untreated and 19 treated) were exposed to a series of 72 slides of pictures of spiders, weapons, and flowers that were randomly paired with either a shock, a siren, or nothing. A posteriori, untreated participants reported an illusory correlation (IC) between spiders and shock. Although the IC was not significantly smaller in treated as compared to untreated participants, no significant IC could be shown in treated participants. For untreated people enhanced shock expectancies were already present on the first spider trials. The IC was paralleled by heightened skin conductance responses (UCRs) on shocks that were preceded by spider slides compared to shocks preceded by other slides. There were positive correlations between IC, on-line expectancies, and UCRs.

Cloning and characterization of MN1, a gene from chromosome 22q11, which is disrupted by a balanced translocation in a meningioma

We have isolated a gene, called MN1, which resides on chromosome 22 and which was found to be disrupted by a balanced translocation (4;22) in meningioma 32. The MN1 gene spans about 70 kb and consists of at least two large exons of approximately 4.7 kb and 2.8 kb. The MN1 cDNA codes for a protein of 1319 amino acids when the first methionine in the open reading frame is used. The MN1 cDNA contains two CAG repeats, one of which codes for a string of 28 glutamines. The t(4;22) disrupts the 5'-exon within the open reading frame. In meningioma 32 no expression of the MN1 mRNA is observed. These results suggest that inactivation of the MN1 gene in this tumour may contribute to its pathogenesis.