Predictive impact of rare genomic copy number variations in siblings of individuals with autism spectrum disorders

Identification of genetic biomarkers associated with autism spectrum disorders (ASDs) could improve recurrence prediction for families with a child with ASD. Here, we describe clinical microarray findings for 253 longitudinally phenotyped ASD families from the Baby Siblings Research Consortium (BSRC), encompassing 288 infant siblings. By age 3, 103 siblings (35.8%) were diagnosed with ASD and 54 (18.8%) were developing atypically. Thirteen siblings have copy number variants (CNVs) involving ASD-relevant genes: 6 with ASD, 5 atypically developing, and 2 typically developing. Within these families, an ASD-related CNV in a sibling has a positive predictive value (PPV) for ASD or atypical development of 0.83; the Simons Simplex Collection of ASD families shows similar PPVs. Polygenic risk analyses suggest that common genetic variants may also contribute to ASD. CNV findings would have been pre-symptomatically predictive of ASD or atypical development in 11 (7%) of the 157 BSRC siblings who were eventually diagnosed clinically.

Interprofessional education in U.S. and Canadian dental schools: an ADEA Team Study Group report

The state of interprofessional education (IPE) in U.S. and Canadian dental schools was studied by the American Dental Education Association (ADEA) Team Study Group on Interprofessional Education. The study group reviewed the pertinent IPE literature, examined IPE competencies for dental students, surveyed U.S. and Canadian dental schools to determine the current and planned status of IPE activities, and identified best practices. Members of the study group prepared case studies of the exemplary IPE programs of six dental schools, based on information provided by those schools; representatives from each school then reviewed and approved its case study. Six reviewers critiqued a draft of the study group's report, and study group members and reviewers met together to prepare recommendations for schools. This report identifies four domains of competence for student achievement in IPE and summarizes responses to the survey (which had an 86 percent response rate). It also includes the case descriptions of six schools' IPE programs and the study group's recommendations for dental schools. The report concludes that there is general recognition of the goals of IPE across U.S. and Canadian dental schools, but a wide range of progress in IPE on the various campuses. Challenges to the further development of IPE are discussed.

Faculty impressions of dental students' performance with and without virtual reality simulation

This study compared faculty perceptions and expectations of dental students' abilities using virtual reality simulation (VRS) to those who did not use virtual reality simulation (non-VRS) in an operative dentistry preclinical course. A sixteen-item survey with a ten-point rating scale and three open-ended questions asked about students' abilities in ergonomics, confidence level, performance, preparation, and self-assessment. The surveys were administered three times to a small group of preclinical faculty members. First, faculty members (n=12, 92 percent response rate) gave their perceptions of non-VRS students' abilities at the end of their traditional course. Secondly, faculty members (n=13, 100 percent response rate) gave their expectations of the next incoming class's abilities (VRS students) prior to the start of the course with traditional and VRS components. Finally, faculty members (n=13, 100 percent response rate) gave their perceptions of VRS students' abilities after completion of the course. A Tukey's test for multiple comparisons measured significance among survey items. Faculty perceptions of VRS students' abilities were higher than for non-VRS students for most abilities examined. However, the faculty members' expectations of VRS training were higher than their perceptions of the students' abilities after VRS training for most abilities examined. Since ergonomic development and technical performance were positively impacted by VRS training, these results support the use of VRS in a preclinical dental curriculum.

Employment of 16 S rDNA gene sequencing techniques to identify culturable environmental eubacteria in a tertiary referral hospital

Universal or 'broad-range' eubacterial polymerase chain reaction (PCR) was performed on 53 isolates from environmental water-associated sites in a haematology unit (N = 22) and the outer surfaces of cleaning lotion containers sited throughout a tertiary referral hospital (N = 31) 16 S rDNA PCR was performed using two sets of universal primers, including the novel reverse primer, XB4, to generate a composite amplicon of 1068 bp, which was sequenced to obtain each isolate's identity. Sequence analysis was able to identify 51 isolates. Most (75% from the haematology unit and 81% from cleaner containers) were Gram-positive. Nine different genera were identified from the haematology unit and 13 from the cleaning lotion containers. This study provides the first reports of Terrabacter spp. and Brachybacterium paraconglomeratum isolated from a hospital environment. As unusual and difficult-to-identify environmental organisms are unlikely to be clinically significant, and molecular identification is costly and labour-intensive, we recommend that molecular methods are only used as an adjunct to first-line phenotypic identification schemes where a definitive identification is required. Where molecular identification methods are justified, partial 16 S rDNA PCR and sequencing employing the novel universal primer XB4, is a valuable and reliable technique.

Experience with virtual reality-based technology in teaching restorative dental procedures

This article reports on extensive experience with advanced simulation at the University of Pennsylvania, School of Dental Medicine (UPSDM). Virtual reality-based technology (VRBT) or advanced simulation is currently available for the instruction of dental students in preclinical restorative procedures. UPSDM was one of the first schools in the world to have extensive experience with VRBT technology using an advanced simulation unit (DentSim) from DenX, Ltd. UPSDM's experience consists of several years of research using control and experimental groups, employing students to participate in an investigative project, and using the units for remediation and a supplement to the preclinical laboratory. Currently, all first-year students (Class of 2007 and Class of 2008) are receiving most of their preparative operative training on the VRBT units. UPSDM started with one (beta) version unit in 1998, which was later updated and expanded first to four units and recently to fifteen units. This communication is presenting the studies that were of fundamental importance in making the decision to acquire fifteen units in 2003. The areas of main interest to the SDM concerning this technology were its use in teaching, refreshing, and remediating students in restorative procedures and its effectiveness as a teaching methodology in relation to time, efficiency, and faculty. Several studies with varying parameters were performed at various time points. The limited statistical analysis conducted was not conclusive for all measures, and in some cases the data only suggest areas of possible significance. This is due to the low number of students who could access the limited number of available units and the change of protocols in response to student and faculty input. Overall, the results do suggest, however, that students learn faster, arrive at the same level of performance, accomplish more practice procedures per hour, and request more evaluations per procedure or per hour than in our traditional laboratories. Students' attitudes, as measured by surveys, group interviews, and private interviews, are mixed. Our overall evaluation of our experience with this technology has been positive and led to the purchase of additional units, its full incorporation into our curriculum, and curriculum revision to maximize its potential. Our conclusion is that this technology offers significant potential in the field of dental education and that further use and investigation are both desired and justified.

Spatial working memory ability is a marker of risk-for-psychosis

BACKGROUND

Working memory has been identified as a core cognitive deficit in schizophrenia that is associated with negative symptoms, but it is unclear whether it is impaired prior to onset of psychosis in symptomatic patients.

METHOD

Thirty-eight young people at ultra high-risk (UHR) of developing psychosis (of whom nine later became psychotic) were compared with 49 healthy controls on tests of spatial working memory (SWM) and delayed matching-to-sample (DMTS).

RESULTS

Both SWM and DMTS performance was significantly poorer in the UHR groups. Those who later became psychotic generally performed more poorly than those who did not, although this did not reach significance for any measure. A significant association between SWM errors and negative symptoms was seen in the later-psychotic group only (P = 0.02).

CONCLUSIONS

Spatial working memory abilities are impaired in those at high-risk for psychosis. The relationship between working memory and negative symptoms may be useful as a predictive tool.

Visuospatial memory and learning in first-episode schizophreniform psychosis and established schizophrenia: a functional correlate of hippocampal pathology?

BACKGROUND

Despite a number of studies that have indicated impaired memory function in patients with schizophrenia, there have been few that have used a sensitive measure of right medial temporal lobe pathology. Given the reported findings of reduced hippocampal volume in schizophrenia, we used a theoretically sensitive test of the right medial temporal lobe to determine the nature of the visuospatial memory deficit in the disorder.

METHODS

Seventy-six patients (37 with a first-episode schizophreniform psychosis, and 39 with established schizophrenia) were compared with 41 comparison subjects on a number of tests of visuospatial memory. These included spatial working memory, spatial and pattern recognition memory and a pattern-location associative learning test.

RESULTS

Both patient groups displayed recognition memory deficits when compared to the comparison group. However, only those patients with established schizophrenia (of 9 years duration on average) were impaired on the associative learning test.

CONCLUSIONS

The results indicate either a progressive decline in visuospatial associative learning ability over the course of the disorder, or that poor visuospatial associative learning is a marker for poor prognosis. In addition, these results have implications for our understanding of the role of the right medial temporal lobe in the pathophysiology of schizophrenia.

A new frameshift mutation encoding a truncated amelogenin leads to X-linked amelogenesis imperfecta

The amelogenin proteins are the most abundant organic components of developing dental enamel. Their importance for the proper mineralization of enamel is evident from the association between previously identified mutations in the X-chromosomal gene that encodes them and the enamel defect amelogenesis imperfecta. In this investigation, an adult male presenting with a severe hypoplastic enamel phenotype was found to have a single base deletion at the codon for amino acid 110 of the X-chromosomal 175-amino acid amelogenin protein. The proband's mother, who also has affected enamel, carries the identical deletion on one of her X-chromosomes, while the father has both normal enamel and DNA sequence. This frameshift mutation deletes part of the coding region for the repetitive portion of amelogenin as well as the hydrophilic tail, replacing them with a 47-amino acid segment containing nine cysteine residues. While greater than 60% of the protein is predicted to be intact, the severity of this phenotype illustrates the importance of the C-terminal region of the amelogenin protein for the formation of enamel with normal thickness.

Use of simulation technology in dental education

Simulation is becoming very beneficial in the area of health care education. Dentistry has used various types of simulation in preclinical education for some time. This article discusses the impact of the current simulation laboratories on dental education and reviews advanced technology simulation that has recently become available or is in the developmental stage. The abilities of advanced technology simulation, its advantages and disadvantages, and its potential to affect dental education are addressed.

Systemic lupus erythematosus presenting with oral mucosal lesions: easily missed?

Two caucasian patients are described in whom oral mucosal lesions were the first manifestation of systemic lupus erythematosus. In both cases the diagnosis was delayed despite histological examination of oral lesions. Treatment with antimalarials and azathioprine was of significant benefit. In the absence of cutaneous or systemic features, distinguishing oral lupus erythematosus from lichen planus and epidermal dysplasia can be difficult, both clinically and on histology, and requires a high index of suspicion.

Delayed and immediate hypersensitivity reactions associated with the use of amalgam

Hypersensitivity to the constituents of dental amalgam is uncommon. When it occurs it typically manifests itself as a lichenoid reaction involving a delayed, type IV, cell-mediated hypersensitivity response. Rarely, a more acute and generalised response can occur involving both the oral mucosa and skin. We describe two cases that illustrate the presentation and management of these two types of reaction.

Characteristics of empirically supported treatments

This study presents a survey of general characteristics of empirically supported treatments (ESTs) identified by the American Psychological Association Division 12 Task Force on the Promotion and Dissemination of Psychological Procedures. Results indicate that the ESTs share the following characteristics: they involve skill building, have a specific problem focus, incorporate continuous assessment of client progress, and involve brief treatment contact, requiring 20 or fewer sessions. Traditional assessment methods, such as intelligence testing, projectives, and objective personality tests such as the MMPI-2, are rarely used in these treatments. Although it is recognized that these findings are in part an artifact of sociological factors present in contemporary psychotherapy development and research, the findings may also serve as a heuristic aid in the development of therapies.

Role of human papillomaviruses in cutaneous and oral manifestations of immunosuppression

Long-term immunosuppressive drug regimes, used to prevent organ transplant rejection, are associated with an increased risk of epithelial malignancies particularly anogenital and cutaneous cancers. Premalignant and malignant lesions of the oral mucosa have also been reported in renal transplant recipients (RTRs), particularly of sun-exposed lip lesions. Many of these anogenital lesions are associated with the detection of high-risk mucosal human papillomaviruses (HPV). Novel degenerate and nested polymerase chain reaction (PCR) techniques have found high levels of epidermodysplasia verruciformis (EV) HPVs (high-risk cutaneous oncogenic HPVs) in cutaneous warts, dysplastic keratoses, and squamous cell carcinomas. Unusual appendageal and spindle cell carcinomas are being observed in RTRs. Increasing survival times of HIV-positive patients may be associated with dysplasia of orogenital mucosal epithelium, and careful epidemiologic studies of cutaneous lesions are needed. The role of HPVs in the development of these lesions has yet to be established.

Investigation of dopamine system genes in obsessive-compulsive disorder

Evidence from anatomical, pharmacological, and animal studies on the involvement of the dopamine system in obsessive-compulsive disorder (OCD) is mounting. This, along with evidence for a genetic diathesis provided by family and twin studies, prompted us to conduct genetic association studies of dopamine system genes in OCD. We genotyped OCD patients (n > 100) and matched controls for four loci: (1) a 40-base-pair repeat in the dopamine transporter gene; (2) the TaqIA polymorphism and the serine/cysteine variation in the D2 dopamine receptor gene; (3) an MscI polymorphism in the D3 dopamine receptor gene; and (4) a 48-base-pair repeat in the D4 dopamine receptor gene. Significant differences in allele frequencies were found between patients and controls for the D4 receptor gene, although replication is required with family-based controls before any conclusions can be entertained. This study represents the first comprehensive assessment of the roles of dopamine system genes in OCD.

Factors associated with weapon use in maternal filicide

The objective of this study was to identify factors associated with weapon use in a group of filicidal women. Clinical data were gathered from the charts of sixty filicidal women evaluated at Michigan's Center for Forensic Psychiatry or through Connecticut's Psychiatric Security Review Board from 1970 to 1996. Factors associated with weapon use were determined using chi squares, ANCOVAS, and a logistic regression. Results were compared to national statistics for child homicide from the Department of Justice Uniform Crime Reports (UCR). Weapon was defined as knife or gun for the study. Weapons were used by one of four women in our study. Guns were used by 13% of filicidal women and knives by 12%. Odds ratio showed that psychotic women were eleven times more likely to kill their child with a weapon than their non-psychotic counterparts (11.2; p = .008). Psychosis was present in every mother who killed her child with a knife and in seven of eight women who killed their children with a gun. Younger children were less likely to be killed with weapons (ANCOVA; F = 8.28; p = .006). This finding was independent of presence or absence of maternal psychosis. These results show that psychotic women are more likely than non-psychotic women to kill their children with weapons. They also show that mothers are more likely to use weapons to kill older children than younger children.

Prototypes of intrafamily homicide and serious assault among insanity acquittees

Public concern with societal violence is intensified when persons who have been found not guilty by reason of insanity (NGRI) of having committed a homicide or serious assault are returned to the community. Successful management of such acquittees in the community requires a sophisticated understanding of the person and the illness within the larger context of the violent incident, the family, the community, and the culture. In this article, we present an analysis of psychotic violence within a family context. A qualitative study of 64 subjects who were found NGRI of killing or seriously injuring a family member resulted in four prototypes of intrafamilial homicide/assault: Till Death Us Do Part; Overwhelming Burden, Elimination of the Limit Setter; and Family-Focused Delusional Killing. The prototypes are presented as a model for developing management strategies both for future risk assessment and for successful transition of the insanity acquittee into the community.

Transfer between atropine-induced spiking in the perirhinal cortex and electrical kindling of the amygdala

We have recently determined that microinfusions of atropine sulphate into the perirhinal cortex (PRC) of adult Sprague-Dawley rats result in the dose dependent generation of epileptiform spike activity. Several observations suggested that atropine-induced spiking (AIS) and amygdaloid kindled seizures may share common neuronal mechanisms: (a) PRC atropine infusions occasionally resulted in the development of generalised seizures resembling those produced by amygdaloid kindling and which were accompanied by simultaneous discharge recorded from the PRC and amygdala, and (b) concurrent low amplitude spiking was occasionally recorded from the amygdala during non-seizure inducing infusions. Using kindling transfer, the present study sought to determine whether AIS possesses some epileptogenic characteristics which are common to an electrically generated afterdischarge. Repeated PRC infusions of atropine sulphate supra-threshold for the elicitation of spiking appeared to produce a positive transfer in that significantly more advanced behavioural seizures were elicited during initial amygdaloid kindling. These findings suggest that AIS (and/or atropine-induced behavioural seizures) and amygdala-kindled seizures share, at some level, common neuronal mechanisms.

Transfer of epileptogenesis between perirhinal cortex and amygdala induced by electrical kindling

An interesting feature of the kindling phenomenon relates to the finding that kindling established in one region of the brain may reduce the number of stimulations required to establish the phenomenon in a second region. It has been proposed that this 'transfer' phenomenon reflects the extent to which seizures arising in two distinct regions share common underlying mechanisms. The perirhinal cortex (PRC) is currently receiving considerable attention with regard to its possible role in epileptogenesis. Although the role of this region in limbic seizures is unclear, the existence of reciprocal connections between the PRC and amygdala provides a possible neural substrate through which these two regions may influence one another. On the basis of this connectivity, one might expect a transfer between PRC kindling and amygdaloid kindling. Using kindling transfer, the present study was formulated to determine the nature of the relationship between electrical kindling of the PRC and amygdala. Animals previously kindled from the PRC to a cortico-generalised level displayed significantly more advanced behavioural seizures during the early stages of amygdaloid kindling than either controls or those partially kindled. This suggests that primary PRC kindling may facilitate amygdaloid access to systems responsible for the generation of motor seizures. Thus, in terms of kindling, the PRC and amygdala appear to be functionally related, with generalised seizures elicited from the PRC and amygdala sharing, at some level, common underlying mechanisms. Finally, the finding that seizures kindled from the dorsal component of the PRC tended to exhibit characteristics which were quite distinct from those elicited by ventral PRC kindling suggests that these two subregions may have different kindling characteristics and/or different patterns of connectivity with the amygdaloid complex.

Golgi membrane skeleton: identification, localization and oligomerization of a 195 kDa ankyrin isoform associated with the Golgi complex

To extend our finding of a Golgi-localized form of the membrane skeleton protein spectrin, we have identified an isoform of ankyrin that associates at steady state with the Golgi complex. Immuno-light and -electron microscopy show that this ankyrin isoform localizes to the perinuclear cytoplasm on tubular vesicular structures that co-stain with Golgi marker proteins. An antiserum raised against erythrocyte ankyrin, which was used to identify the Golgi ankyrin, recognized three prominent polypeptides of 220, 213 and 195 kDa in MDCK cells. Affinity purification of this antiserum against each of these MDCK cell ankyrins revealed that only an antibody specific for the 195 kDa form retained the ability to stain the Golgi complex; affinity purified antibody preparations specific for both the 220 and 213 kDa forms stained punctate and reticular cytoplasmic structures distinct from the Golgi complex. Antibody specific for the 195 kDa ankyrin did not recognize a recently identified 119 kDa ankyrin that is also localized to the Golgi. The 195 kDa Golgi ankyrin binds purified erythrocyte spectrin, and rapidly co-sediments with Golgi beta-spectrin during brief, low speed centrifugation of Triton X-100 extracts of MDCK cells. Golgi ankyrin and beta-spectrin are retained on tubular vesicular ‘Golgi ghosts’ following extraction of cultured cells with Triton X-100. Significantly, Golgi ghost tubules containing ankyrin/spectrin are co-linear with individual microtubules, suggesting a role for both Golgi membrane skeleton and microtubules in spatial localization of the Golgi. Golgi ankyrin dissociates from Golgi membranes during mitosis and in cells treated with brefeldin A, indicating that Golgi ankyrin has a dynamic assembly state similar to that of Golgi spectrin and other Golgi membrane coat proteins.

Association study of dopamine D3 receptor gene and schizophrenia

Several groups have reported an association between schizophrenia and the MscI polymorphism in the first exon of the dopamine D3 receptor gene (DRD3). We studied this polymorphism using a North American sample (117 patients plus 188 controls) and an Italian sample (97 patients plus 64 controls). In the first part of the study, we compared allele frequencies of schizophrenia patients and unmatched controls and observed a significant difference in the total sample (P = 0.01). The second part of the study involved a case control approach in which each schizophrenia patient was matched to a control of the same sex, and of similar age and ethnic background. The DRD3 allele frequencies of patients and controls revealed no significant difference between the two groups in the Italian (N = 53) or the North American (N = 54) matched populations; however, when these two matched samples were combined, a significant difference was observed (P = 0.026). Our results suggest that the MscI polymorphism may be associated with schizophrenia in the populations studied.

Association study between the dopamine D4 receptor gene and schizophrenia

The dopamine D4 receptor is of major interest in schizophrenia research due to its high affinity for the atypical neuroleptic clozapine and a high degree of variability in the receptor gene (DRD4). Although several genetic linkage analyses performed on schizophrenia multiplex families from different regions of the world have either excluded or failed to prove that DRD4 is a major genetic factor for the development of schizophrenia, analyses for moderate predisposing effects are still of significant interest. We performed a study examining differences in allele frequencies of 4 different DRD4 polymorphisms in schizophrenia patients and age, sex, and ethnic origin matched controls. None of these 4 polymorphisms showed evidence for genetic association with schizophrenia, although a trend towards excess of the allele with 7 repeats in the (48)n bp exon III polymorphism was observed. Complexities in the DRD4 genetic investigation and further analytic approaches are discussed.

Atypical palatal ulceration

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Linkage analysis of the nail-patella syndrome

Nail-patella syndrome (NPS) is an autosomal dominant disorder characterized by dysplasia of nails and patella, decreased mobility of the elbow, iliac horns, and, in some cases, nephropathy. The disorder has been mapped to the long arm of chromosome 9, but the precise localization and identity of the NPS gene are unknown. Linkage analysis in three NPS families, using highly informative dinucleotide repeat polymorphisms on 9q33-q34, confirmed linkage of NPS to this chromosome. Recombinations were detected, by two-point linkage analysis, between NPS and the centromeric markers D9S60 and the gelsolin gene and the telomeric markers D9S64 and D9S66, in one of the families. Haplotype analysis suggested an additional recombination between NPS and the argininosuccinate synthetase (ASS) gene. These results localize the NPS gene to an interval on 9q34.1, distal to D9S60 and proximal to ASS, comprising a genetic distance of approximately 9 cM. This represents a significant refinement in the localization of the NPS gene.

Bone-marrow transplantation in Hurler's syndrome. Effect on skeletal development

Between 1980 and 1988, displacement bone-marrow transplantation was performed on 25 children with Hurler's syndrome (type-1 mucopolysaccharidosis). We describe the musculoskeletal development of 11 of the 12 surviving children and the orthopaedic procedures undertaken to treat progressive thoracolumbar kyphosis, hip subluxation and carpal tunnel syndrome. We found abnormal bone modelling, focal failures of ossification and an avascular disorder of the femoral head in every patient and offer an explanation for these phenomena. Increasing valgus deformity of the knees and progressive generalised myopathy caused loss of mobility as the children entered adolescence. The benefit of bone-marrow transplantation as a treatment for the skeletal disorders of Hurler's syndrome is limited by the poor penetration of the musculoskeletal tissues by the enzyme derived from the leucocytes.

Bone-marrow transplantation in Hurler's syndrome. Effect on skeletal development

Between 1980 and 1988, displacement bone-marrow transplantation was performed on 25 children with Hurler's syndrome (type-1 mucopolysaccharidosis). We describe the musculoskeletal development of 11 of the 12 surviving children and the orthopaedic procedures undertaken to treat progressive thoracolumbar kyphosis, hip subluxation and carpal tunnel syndrome. We found abnormal bone modelling, focal failures of ossification and an avascular disorder of the femoral head in every patient and offer an explanation for these phenomena. Increasing valgus deformity of the knees and progressive generalised myopathy caused loss of mobility as the children entered adolescence. The benefit of bone-marrow transplantation as a treatment for the skeletal disorders of Hurler's syndrome is limited by the poor penetration of the musculoskeletal tissues by the enzyme derived from the leucocytes.

Golgi spectrin: identification of an erythroid beta-spectrin homolog associated with the Golgi complex

Spectrin is a major component of a membrane-associated cytoskeleton involved in the maintenance of membrane structural integrity and the generation of functionally distinct membrane protein domains. Here, we show that a homolog of erythrocyte beta-spectrin (beta I sigma*) co-localizes with markers of the Golgi complex in a variety of cell types, and that microinjected beta-spectrin codistributes with elements of the Golgi complex. Significantly, we show a dynamic relationship between beta-spectrin and the structural and functional organization of the Golgi complex. Disruption of both Golgi structure and function, either in mitotic cells or following addition of brefeldin A, is accompanied by loss of beta-spectrin from Golgi membranes and dispersal in the cytoplasm. In contrast, perturbation of Golgi structure without a loss of function, by the addition of nocodazole, results in retention of beta-spectrin with the dispersed Golgi elements. These results indicate that the association of beta-spectrin with Golgi membranes is coupled to Golgi organization and function.

Molecular genetic predictive testing for Alzheimer's disease: deliberations and preliminary recommendations

Forty-one participants representing diverse professional back-grounds attended a workshop on genetic predictive testing for familial Alzheimer's disease (FAD) on January 23, 1993 at Surrey Place Centre in Toronto, Canada. Rapidly emerging molecular genetic findings in AD indicate that predictive testing is now technologically feasible for selected individuals, although defining eligibility criteria remains problematic. Legal, ethical, biomedical, and psychosocial issues related to establishing predictive testing programs for AD were discussed at the workshop. This article reflects these discussions, provides the current biomedical background for them and examines the Huntington's disease (HD) predictive testing experience. Observations concerning molecular genetic predictive testing for AD in light of its genetic heterogeneity and clinical characteristics, such as usual later age of onset than HD, are presented. It is proposed that predictive testing for AD can now be cautiously offered in a research setting primarily according to the recommendations contained within the Ethical Issues Policy Statement on Huntington's Disease Molecular Genetics Predictive Test. However, in their application to AD, some points in the statement are considered to require emphasis, modification, or currently to be of uncertain applicability. This represents an initial step in an on-going process of debate concerning AD that will be required as new advances occur in genetic and clinical research and in bioethics.

Bilateral parotid enlargement as a presenting feature of bulimia nervosa in a post-adolescent male

An unusual case of bulimia nervosa in a post-adolescent male is reported. The clinical presentation was one of painless parotid swelling of 3 years duration with marked weight loss and underlying metabolic alkalosis. The diagnostic significance of parotid salivary gland swellings is discussed.

Mortality of workers at the Hanford site: 1945-1986

Updated analyses of mortality of workers at the Hanford site provide little evidence of a positive correlation of cumulative occupational radiation dose and mortality from leukemia and from all cancer except leukemia. Estimates of the excess relative risk per 10 mSv were negative for both disease categories, but these estimates are consistent both with no risk and with estimates obtained through extrapolation from high-dose data. For all cancer except leukemia, the upper limit for a two-sided 90% confidence interval was about 1.5 times the prediction of the BEIR V model, but several times the estimate recommended by the ICRP 60 committee. For leukemia, the comparable upper limit was very close to that predicted by either BEIR V or ICRP 60. The all-cancer risk estimate, from a recent report on updated analyses of data for Oak Ridge National Laboratory workers, was strongly rejected based on the Hanford data. Of 24 specific cancer categories evaluated, only cancer of the pancreas and Hodgkin's disease showed positive correlations with radiation dose that approached statistical significance with one-tailed p values of 0.07 and 0.04, respectively; these correlations are interpreted as probably spurious. For multiple myeloma, for which a correlation was reported previously, the p value was 0.10. However, a significant correlation (p < .05) was obtained when analyses were expanded to include deaths with multiple myeloma listed on the death certificate but not considered to be the underlying cause, when analyses were expanded to include deaths occurring in Washington State during the time period 1987-1989, or when a 2-y latency period (instead of 10-y) was assumed.

Isolation and regional localization of 25 anonymous DNA probes on a chromosome 13 hybrid panel

Clones were isolated from two flow-sorted chromosome 13 libraries. Twenty-five clones were localized to various regions of chromosome 13, using a well-characterized panel of rodent x human hybrid cell lines. Eight DNA markers were localized to 13q14.2----q22, where the gene for Wilson disease, a recessive disorder of copper metabolism, was previously assigned. The new markers will be useful for the diagnosis of presymptomatic sibs of Wilson disease patients. We isolated six DNA clones proximal to the retinoblastoma gene, a region in which a translocation associated with rhabdomyosarcoma has been observed. Probes for both of these regions will be useful for the cloning of the genes involved in these diseases.

Transformed sweat gland and nasal epithelial cell lines from control and cystic fibrosis individuals

We undertook to extend the in vitro lifespan of epithelial cell cultures useful for the study of the cellular defect underlying cystic fibrosis (CF). Primary cultures from sweat glands of four CF and four non-CF and from nasal polyps of one non-CF and two CF individuals were transformed using a chimaeric virus, Ad5/SV40 1613 ori-. The extended lifespans ranged from 20 to more than 250 population doublings beyond that of the primary cultures. Despite some degree of aneuploidy (as assayed by total cellular DNA content) all samples tested retained at least one copy of the region of chromosome 7 containing the CF gene (as assayed by probing with flanking DNA markers). Epithelial characteristics, including an epithelioid morphology, tight junctions and desmosomes, apical microvilli, keratin networks, and dome formation were positive in the majority of cells examined, although variably expressed. All cells tested demonstrated outwardly rectifying chloride channels by patch clamp, with some from non-CF cells responsive to the catalytic subunit of cyclic AMP-dependent protein kinase. The cells were used for DNA transfection assays with selectable marker genes in appropriate vectors, in order to develop methodology for assaying the function of the CF gene product and the effects of mutations.

Saccular oesophageal diverticulum at the site of enucleation of a leiomyoma

A case of saccular diverticulum of the oesophagus occurring at the site of enucleation of an oesophageal leiomyoma is presented. Implication for surgical therapy are discussed.

Identification of the cystic fibrosis gene: genetic analysis

Approximately 70 percent of the mutations in cystic fibrosis patients correspond to a specific deletion of three base pairs, which results in the loss of a phenylalanine residue at amino acid position 508 of the putative product of the cystic fibrosis gene. Extended haplotype data based on DNA markers closely linked to the putative disease gene locus suggest that the remainder of the cystic fibrosis mutant gene pool consists of multiple, different mutations. A small set of these latter mutant alleles (about 8 percent) may confer residual pancreatic exocrine function in a subgroup of patients who are pancreatic sufficient. The ability to detect mutations in the cystic fibrosis gene at the DNA level has important implications for genetic diagnosis.

Identification of the cystic fibrosis gene: genetic analysis

Approximately 70 percent of the mutations in cystic fibrosis patients correspond to a specific deletion of three base pairs, which results in the loss of a phenylalanine residue at amino acid position 508 of the putative product of the cystic fibrosis gene. Extended haplotype data based on DNA markers closely linked to the putative disease gene locus suggest that the remainder of the cystic fibrosis mutant gene pool consists of multiple, different mutations. A small set of these latter mutant alleles (about 8 percent) may confer residual pancreatic exocrine function in a subgroup of patients who are pancreatic sufficient. The ability to detect mutations in the cystic fibrosis gene at the DNA level has important implications for genetic diagnosis.

DNA marker haplotype association with pancreatic sufficiency in cystic fibrosis

Patients with cystic fibrosis (CF) generally suffer from chronic obstructive lung disease, pancreatic insufficiency (PI), and a number of other exocrine malfunctions. Approximately 15% of CF patients are, however, pancreatic sufficient. To investigate whether the two clinical subgroups, PI and pancreatic sufficiency (PS), are caused by different CF mutant alleles, we have performed linkage disequilibrium and haplotype association analysis with three DNA markers that are tightly linked to the CF locus. The study showed that the allelic and haplotype distributions for these RFLPs are significantly different between the two groups. The data suggest that most of the CF-PI patients are probably descendants of a single mutational event at the CF locus and that the CF-PS patients resulted from multiple, different mutations. While final interpretation of these data awaits molecular cloning of the CF gene, the information on haplotype association in CF may be useful in genetic counseling and disease prognosis, in identifying the gene itself, and in defining the mutations.

Cyclic AMP induces changes in distribution and transport of organelles within growth cones of Aplysia bag cell neurons

This report examines cAMP-induced regulation of directed organelle transport in bag cell neuron growth cones using video-enhanced differential interference contrast (DIC) microscopy (Allen et al., 1981; Inoue, 1981) and digital image analysis techniques. Under control conditions, organelle transport is evident in the central cytoplasmic regions of bag cell neuron growth cones, but not in lamellae. Motility of lamellae takes the form of slow (less than 0.01 micron/sec) extension of margins and ruffling motions that propagate as waves (velocity, approximately 0.07 micron/sec) in a retrograde direction. Application of forskolin and a phosphodiesterase (PDE) inhibitor at concentrations known to induce changes in bag cell protein phosphorylation resulted in (1) rapid extension of directed organelle transport into lamellae, and (2) inhibition of the retrograde ruffling waves. These changes effected transformation of lamellae into neurite endings packed with microtubules and organelles, a large proportion of which appeared to be neurosecretory granules. The effects were reversible, dose-dependent, potentiated by a variety of PDE inhibitors, and mimicked by 6-N-butyl-8-benzyl-thio-cAMP (BT-cAMP). Though forskolin may normally promote depolarization and Ca entry, these changes in growth cone structure are not secondary to influx of external Ca, as they persist in Ca-free/EGTA solutions; furthermore, they do not resemble the effects of depolarization induced by perfusion with elevated K solutions. The cAMP-induced changes in growth cone morphology that we report here suggest a possible role for protein phosphorylation in promoting growth cone differentiation and structural changes accompanying secretion.

Genetic markers for assessment of retinoblastoma predisposition

Here we provide a conceptual framework for the application of current approaches in the analysis of retinoblastoma to the clinical setting. The aim of genetic medicine is to minimize the burden of inherited disease through appropriate diagnosis and management of patients and to maximize information, so that families can make reasonable decisions about reproduction. Recent genetic, cytogenetic and molecular genetic approaches have improved our understanding of the biological events leading to the occurrence of retinoblastoma and, in addition, have provided tools for the enhanced assessment of risk for some individuals. The knowledge, however, is incomplete and the tools imperfect, as indicated by our continued provision of risk probabilities that are neither one nor zero. We therefore hope to emphasize both the scope and the limitations of these techniques so that their application can be effectively considered.