Myers-Briggs Type Indicator and dental school performance

The Myers-Briggs Type Indicator (MBTI) was administered to 256 dental students, representing four classes, at the University of Florida College of Dentistry. The results of this psychological instrument were then correlated with overall dental school performance based on results from the National Dental Board Examinations Part I and II (NB-I, NB-II), yearly class rank, and specific academic difficulties as measured by the Student Performance Evaluation Committee. Introverted students were found to display a significantly increased performance on NB-I (p = .038) and NB-II (p = .044). They were also found, however, to demonstrate a progressively lower class rank over the four-year period than extroverted students and were more likely to experience major academic difficulties as well. Judging and sensing individuals were found to earn a higher class rank over the four-year period than perceiving and intuitive students, respectively. Perceiving students were found to exhibit major difficulties or were placed on probation more often than judging individuals. These results may prove useful in counseling students to recognize potential problems before they commence their dental education or to anticipate and address specific weaknesses during the course of their education.

Molecular genetic and phenotypic analysis reveals differences between TSC1 and TSC2 associated familial and sporadic tuberous sclerosis

Tuberous sclerosis (TSC) is an autosomal dominant disorder characterised by the development of hamartomatous growths in many organs. Sixty to seventy percent of cases are sporadic and appear to represent new mutations. TSC exhibits locus heterogeneity: the TSC2 gene is located at 16p13.3 whilst the TSC1 gene, predicted to encode a novel protein termed hamartin, has recently been cloned from 9q34. With the exception of a contiguous gene deletion syndrome involving TSC2 and PKD1 , TSC1 and TSC2 phenotypes have been considered identical. We have now comprehensively defined the TSC1 mutational spectrum in 171 sequentially ascertained, unrelated TSC patients by single strand conformation polymorphism and heteroduplex analysis of all 21 coding exons, and by assaying a restriction fragment spanning the whole locus. Mutations were identified in 9/24 familial cases, but in only 13/147 sporadic cases. In contrast, a limited screen revealed TSC2 mutations in two of the familial cases and in 45 of the sporadic cases. Thus TSC1 mutations were significantly under-represented among sporadic cases (Fisher's exact p -value = 3.12 x 10(-4)). Both large deletions and missense mutations were common at the TSC2 locus whereas most TSC1 mutations were small truncating lesions. Mental retardation was significantly less frequent among carriers of TSC1 than TSC2 mutations (odds ratio 5.54 for sporadic cases only, 6.78 +/- 1.54 when a single randomly selected patient per multigeneration family was also included). No correlation between mental retardation and the type of mutation was found. We conclude that there is a reduced risk of mental retardation in TSC1 as opposed to TSC2 disease and that consequent ascertainment bias, at least in part, explains the relative paucity of TSC1 mutations in sporadic TSC.

The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis

Tuberous sclerosis is an autosomal dominant trait in which the dysregulation of cellular proliferation and differentiation results in the development of hamartomatous growths in many organs. The TSC2 gene is one of two genes determining tuberous sclerosis. Inactivating germline mutations of TSC2 in patients with tuberous sclerosis and somatic loss of heterozygosity at the TSC2 locus in the associated hamartomas indicate that TSC2 functions as a tumour suppressor gene and that loss of function is critical to expression of the tuberous sclerosis phenotype. The TSC2 product, tuberin, has a region of homology with the GTPase activating protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in vitro. Here we show that the region of homology between tuberin and human rap1GAP and the murine GAP mSpa1 is more extensive than previously reported and spans approximately 160 amino acid residues encoded within exons 34-38 of the TSC2 gene. Single strand conformation polymorphism analysis of these exons in 173 unrelated patients with tuberous sclerosis and direct sequencing of variant conformers together with study of additional family members enabled characterisation of disease associated mutations in 14 cases. Missense mutations, which occurred in exons 36, 37 and 38 were identified in eight cases, four of whom shared the same recurrent change P1675L. Each of the five different missense mutations identified was shown to occur de novo in at least one sporadic case of tuberous sclerosis. The high proportion of missense mutations detected in the region of the TSC2 gene encoding the GAP-related domain supports its key role in the regulation of cellular growth.

Idiopathic torsion dystonia linked to chromosome 8 in two Mennonite families

The DYT1 locus on chromosome 9q34 is responsible for most childhood limb-onset idiopathic torsion dystonia (ITD). Linkage to DYT1 has been excluded in families with adult-onset, and predominantly cranial-cervical, ITD. We mapped a locus (DYT6) associated with prominent cranial-cervical ITD in two large Mennonite families to chromosome 8. An identical haplotype spanning 40-cM segregates with ITD in these families, suggesting a shared mutation from the recent past.

A flagellar sheath protein of Helicobacter pylori is identical to HpaA, a putative N-acetylneuraminyllactose-binding hemagglutinin, but is not an adhesin for AGS cells

The gene encoding a 29-kDa flagellar sheath protein was cloned and found to be similar to hpaA, reported to encode an N-acetylneuraminyllactose-binding fibrillar hemagglutinin (D. G. Evans, T. K. Karjalainen, D. J. Evans, Jr., D. Y. Graham, and C. H. Lee, J. Bacteriol. 175:674-683, 1993). The transcriptional start was mapped by primer extension from Helicobacter pylori mRNA, indicating an active consensus promoter at a location different from that suggested by Evans et al. Immunogold labelling of the flagellar sheath with a monoclonal antibody to HpaA was demonstrated in four strains, contrary to previous reports of a surface (D. G. Evans, T. K. Karjalainen, D. J. Evans, Jr., D. Y. Graham, and C. H. Lee, J. Bacteriol. 175:674-683, 1993) or a cytoplasmic (P. W. O'Toole, L. Janzon, P. Doig, J. Huang, M. Kostrzynska, and T. J. Trust, J. Bacteriol. 177:6049-6057, 1995) locale. Agglutination of erythrocytes and adherence to AGS cells by a delta hpaA mutant were no different from those of the parent strain, confirming a recent finding of O'Toole et al.

Affective responses to acute exercise: a test of opponent-process theory

Based on Solomon's Opponent-Process theory (1980), it was predicted that individuals involved in a regimen of regular aerobic exercise (active; n = 18) would respond to an acute bout of exercise with reduced negative and/or increased positive affect compared to nonactive counterparts (nonactive; n = 12). State Anxiety (SA), positive affect (PA), negative affect (NA), and self-reported fatigue were assessed immediately prior to, every 6 min during, and every 6 min following a 24 min bout of bicycle exercise performed at an RPE of 13 (+/- 1). As expected, no significant group differences occurred for RPE (M = 13.5 for nonactive, 13.2 for active). The active group did, however, exercise at a greater absolute workload than the nonactive group (261.0 +/- 22.4 W vs 200.0 +/- 19.98 W, respectively). Analyses indicated similar changes in SA and fatigue for both groups, with significant reductions in SA occurring at 6 min post-exercise and remaining below pre-exercise levels throughout the post-exercise period, while fatigue was reduced at 12, 18, and 24 min post-exercise. A significant Group x Time interaction occurred for affective valence (PA - NA; p < .01). Post hoc analyses indicated that for the active group, affect increased modestly (i.e., more PA, less NA) during exercise; this increase was sustained post-exercise. The nonactive group evidenced a sharp drop in affect (i.e., less PA, more NA) during exercise followed by a small post-exercise rise which did not return to pre-exercise levels. The results of the present study partially support the Opponent-Process model as an explanation for exercise-related affect. Although there was no differential anxiety response as a function of activity level as the model would predict, there was a differential response for affective valence in accordance with predictions.

Identification of the tuberous sclerosis gene TSC1 on chromosome 9q34

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the widespread development of distinctive tumors termed hamartomas. TSC-determining loci have been mapped to chromosomes 9q34 (TSC1) and 16p13 (TSC2). The TSC1 gene was identified from a 900-kilobase region containing at least 30 genes. The 8.6-kilobase TSC1 transcript is widely expressed and encodes a protein of 130 kilodaltons (hamartin) that has homology to a putative yeast protein of unknown function. Thirty-two distinct mutations were identified in TSC1, 30 of which were truncating, and a single mutation (2105delAAAG) was seen in six apparently unrelated patients. In one of these six, a somatic mutation in the wild-type allele was found in a TSC-associated renal carcinoma, which suggests that hamartin acts as a tumor suppressor.

Mapping of familial primary pulmonary hypertension locus (PPH1) to chromosome 2q31-q32

BACKGROUND

The pathogenesis of primary pulmonary hypertension (PPH) is unknown, although in some instances families with multiple affected members suggest a genetic etiology.

METHODS AND RESULTS

We used microsatellite markers and linkage analysis in a large family with PPH to determine the chromosomal location of their disease gene. We tested a second, ethnically distinct, family for cosegregation of disease with markers from the linked region. We mapped the disease locus PPH1; GDB/HUGO designation (GDB:1381541; July 1996), approved when this work was accepted for publication in abstract form (Circulation. 1996;94[suppl I]:1-49.), in these families to a 27-cM region on chromosome 2q31-q32, with a maximum lod score of 3.87 associated with markers D2S350 and D2S364.

CONCLUSIONS

Cosegregation of this region with disease in different ethnic groups suggests that we mapped an important locus in familial PPH. Careful study of additional families and sporadic cases will be required to confirm this localization of PPH1 and characterize its overall role.

Community nurse education in leg ulcer management

An audit of a wound-care training project implemented in conjunction with an initiative to set up community leg ulcer clinics

Macrognathia of renal osteodystrophy in dialysis patients

A multiinstitutional study of macrognathia secondary to renal osteodystrophy in dialysis patients is presented. The nine cases reviewed reveal a variety of radiographic and histopathologic features, some of which resemble fibrous dysplasia and others suggestive of Paget's disease of bone. This article contains diagnostic criteria for differentiating renal osteodystrophy from similar fibro-osseous proliferations along with a discussion of the underlying cause and appropriate therapeutic interventions.

Immune responses during pregnancy and the development of allergic disease

It is now established that allergen exposure in the first few months of life is important in the development of specific allergic sensitisation (1, 2). Furthermore, the immune response of infants born to families with a strong history of allergic disease is relatively immature at birth in comparison to infants with no family history of allergies, with reduced production of Interferon-gamma (IFN-gamma) (3-5) and lower levels of T cell activation and memory (6). It therefore seems logical that the interaction of these two factors must be important in the ontogeny of allergic disease.

Prenatal origins of asthma and allergy

The prevalence of asthma and related allergic disorders has increased considerably over the last 25 years. Genetic stock has not changed, so environmental factors must have influenced the phenotype. Infants who develop allergy already have an altered immune response at birth. We have investigated the development of immune responses during gestation and the effect of maternal allergen exposure during pregnancy and infant exposure in the first month of life on the development of allergy and disease. There was higher specific peripheral blood mononuclear cell proliferation to house dust mite (P = 0.01) and birch pollen (P = 0.004) in the third trimester compared with the second trimester, with the first positive responses seen at 22 weeks gestation. Maternal exposure to birch pollen after 22 weeks resulted in higher (P = 0.005) infant peripheral blood mononuclear cell responses to birch pollen at birth. Infants born at term, with at least one atopic, asthmatic parent, who developed allergic symptoms and positive skin prick test by one year of age had raised proliferative responses to house dust mites at birth compared to those with no symptoms (P = 0.01). In genetically predisposed individuals, antenatal factors, including maternal and thereby fetal exposure to allergens and maternoplacental-fetal immunological interactions, are active in determining whether an allergic predisposition is manifested as disease.

Clinical audit and effective change in leg ulcer services

An audit of clinical leg ulcer services was undertaken in South Bedfordshire and was followed by a process of implementation using research-based methods; a re-audit was conducted 18 months later. Using an adaptation of the Riverside model, patients were referred to community leg ulcer clinics. They were assessed using Doppler ultrasound; those with ABPI > 0.8 were treated using a high-compression four-layer bandage system. Those with ABPI 0.6-0.8 were treated using reduced compression, and those with ABPI < 0.6 were sent to their GP for referral for specialist opinion. In October 1993, the average cost of consumables for each patient was 8.53 pounds, and this rose to 10.14 pounds in May 1995. However, patients treated in community clinics had a reduced cost of consumables of 7.91 pounds compared with 10.78 pounds for patients treated at home. There was also a corresponding reduction in weekly treatments and an overall reduction in nursing time to treat patients. In 111 patients (134 limbs) treated by high compression in the community clinics, cumulative percentage healing was 54% after 12 weeks and 68% after 24 weeks. Although these results were lower than those achieved in the Riverside project, much of the difference can be explained by the different patient populations and ulcer duration. The results support a system of care which offers rationalisation of service, staff training and research-based effective assessment and treatment.

Fetal peripheral blood mononuclear cell proliferative responses to mitogenic and allergenic stimuli during gestation

Blood samples were obtained from fetuses and premature babies (n = 51) (15-34 weeks gestation) to determine at what stage the fetal immune system was able to produce a positive proliferative response to common allergens. Peripheral blood mononuclear cells (PBMC) were stimulated with the mitogen, phytohaemagglutinin (PHA), and the allergens, house dust mite, cat fur, birch tree pollen, beta-lactoglobulin, ovalbumin and bee venom (mellitin). Results were expressed as ratios of stimulated to unstimulated 3H thymidine incorporation, and as percent positive responders. There was an increase in proliferation ratio which correlated with increasing gestational age for PHA (p < 0.0001), cat fur (p = 0.042), birch pollen (p = 0.022) and beta-lactoglobulin (p = 0.006). The point in gestation when cells from some individuals began responding to the allergens with a ratio of 2.0 was at approximately 22 weeks. PBMC proliferative response ratios were higher from samples from babies > 22 weeks gestation compared to < 22 weeks for the mitogen and all allergens, except mellitin. There was also a greater proportion of positive responders from samples > 22 weeks compared to < 22 weeks for the mitogen and all allergens, except mellitin. Maternal exposure to birch pollen, which has a discrete season, was assessed to determine whether exposure had occurred at 22 weeks gestation or beyond. Results showed a higher proliferative response in infant cells stimulated with birch pollen (p = 0.005) and higher proportion of positive responders (p = 0.01) in the group of babies whose mothers had been exposed to birch pollen beyond 22 weeks, compared to those whose mothers had not been so exposed. These results suggest that in utero fetal exposure to an allergen from around 22 weeks gestation may result in primary sensitisation to that allergen, leading to positive proliferative responses, at birth.

Indispensable amino acid deficiency and increased seizure susceptibility in rats

Repeated subthreshold stimulation of limbic brain areas increases seizure susceptibility in experimental models of epilepsy. In addition, acute dietary indispensable amino acid (IAA) deficiency activates the anterior piriform cortex (APC), a seizure-prone limbic brain area in the rat. Based on these two findings, we hypothesized that activation of the APC by chronic exposure to IAA-deficient diets might increase seizure susceptibility. Several nonessential amino acid neurotransmitters are important in seizures, but deficiencies of nontransmitter IAAs have not been well studied in seizure models. In four trials, we made injections of pentylenetetrazole intraperitoneally or of bicuculline into the APC in histidine-, isoleucine-, or threonine-deficient rats and controls. Increased susceptibility to seizures in the deficient animals was observed as increased severity of the seizures, decreased threshold for the dose of the chemostimulant and time to seizure, or a combination thereof. Pair-fed controls showed that this effect was not due to an energy deficit. This novel but robust finding suggests that IAA deficiency may increase vulnerability to seizures by repeated activation of the APC.

Human papillomavirus-associated oral epithelial dysplasia (koilocytic dysplasia): an entity of unknown biologic potential

Intraepithelial neoplasia of the female genital tract has long been associated with human papillomavirus infection. To date, there have been no previously published studies of oral dysplasia that have identified light microscopic features predictive of the presence of human papillomavirus. We identified a variant of oral epithelial dysplasia, koilocytic dysplasia, that exhibited light microscopic features suggestive of HPV infection. To determine if these microscopic features were specifically correlated with human papillomavirus infection, DNA in situ hybridization for human papillomavirus 6/11, 16/18, and 31/33/51 was performed on 31 lesions diagnosed histologically as koilocytic dysplasia. Seventeen matched control cases of conventional oral epithelial dysplasia were also analyzed for human papillomavirus. Human papillomavirus DNA was detected significantly more often (p < 0.001) in koilocytic dysplasia (80.6%) than conventional oral epithelial dysplasia (0.0%). Positive cases of koilocytic dysplasia contained either intermediate-risk (31/33/51) or high-risk (16/18) human papillomavirus types whether or not they contained low-risk human papillomavirus types (6/11). The histologic and clinical presentation of koilocytic dysplasia was unique. Lesions demonstrated koilocytes and other microscopic characteristics of human papillomavirus infection, as well as features of conventional epithelial dysplasia. A striking male predominance was noted, as was a relatively young average age of presentation (39.0 years). On the basis of our preliminary analysis, we conclude that oral koilocytic dysplasia represents a unique pathologic entity and that the presence of human papillomavirus can be predicted on light microscopy with at least 80% accuracy. The clinical significance and potential for malignant transformation of koilocytic dysplasia remain to be investigated.

Peripheral blood mononuclear cell proliferative responses in the first year of life in babies born to allergic parents

BACKGROUND

Raised peripheral blood mononuclear cells (PBMCs) proliferative responses to food allergens have been demonstrated in children with established atopic dermatitis.

OBJECTIVE

In this report we investigate the PBMC proliferative responses to inhalant and food allergens from babies at birth, 6 months and 1 year of age, born to atopic and non-atopic parents.

METHODS

PBMCs, separated by density gradient centrifugation, were cultured for 6 days with autologous plasma and a range of allergens (house dust mite [HDM], cat, grass pollen, tree pollen, betalactoglobulin and ovalbumin). Proliferative responses were measured by the uptake of [3H] thymidine added for the final 18 h of culture.

RESULTS

At birth, infants born to atopic parents who developed allergic disease by 1 year of age had significantly more positive responses (stimulation index > or = 2 with a value of > or = 1000 cpm above background) to HDM (P = 0.0097), betalactoglobulin (P = 0.0166) and ovalbumin (P = 0.0035) than newborns who did not develop allergy. Infants who developed allergy also had significantly more positive responses to HDM (P = 0.03) and ovalbumin (P = 0.0057) than babies, born to non-atopic parents, who did not develop allergies. At 6 months of age a significant fall in response to HDM (P = 0.003) and cat fur extract (P = 0.006) was seen in infants who developed allergic disease by 1 year of age. A similar pattern was seen for proliferative responses to betalactoglobulin and ovalbumin (P = 0.0006, P = 0.004). Conversely, proliferations to grass and tree pollen extracts increased at 6 months (P = 0.04, P = NS) and 1 year (P = NS, P = 0.01) compared with birth which was significant for infants who did not develop allergic disease.

CONCLUSION

Proliferative responses to seasonal allergens increased over the first year of life whilst those to perennial allergens, both inhalant and food, fell. This suggests either the induction of a systemic immune tolerance by perennial exposure to antigens or movement of sensitized cells to target organs where allergen exposure occurs. This process may be independent of the development allergic disease.