POTENTIAL FALSE-POSITIVE RESULTS WITH ANTIGEN ENHANCEMENT FOR IMMUNOHISTOCHEMISTRY OF THE p53 GENE PRODUCT IN COLORECTAL NEOPLASMS

Aberrant crypt foci (ACF) are putative precursor lesions of colon cancer, recently identified on the methylene blue-stained mucosal surface of human colon. No mutations in K- ras or p53 genes were found by non-radioactive single-strand conformation polymorphism analysis in 14 ACF collected from five patients. Using the more sensitive method of allele-specific polymerase chain reaction (PCR) for K- ras , 8 of 14 ACF were found to contain K- ras mutations, suggesting that mutated cells are present in minute clones in ACF. No dysplasia was observed in any of the ACF containing a mutated clone. The presence of K- ras mutations in ACF suggests that these lesions occur at a very early stage in human colorectal carcinogenesis.     

Effect of human saliva on surface degradation of composite resins

Abstract – The amount of methacrylic acid produced by incubation of the dimethacrylate ester TEGDMA in human whole saliva was measured. The conversion rate of TEGDMA was determined in stimulated saliva from dental students and in unstimulated saliva from both dental students and patients. The differences in mean conversion rate measured in the three groups were not statistically significant ( P= 0.346). The mean conversion rate ± SD for all saliva samples was 4.54 ± 3.24 μmol MAA/L. h. The surface of BISGMA/TEGDMA-polymer specimens treated with porcine liver esterase in activities equivalent to those found in human saliva exhibited a lower Wallace microhardness than the surface of untreated specimens. Polymer specimens incubated in human saliva exhibited a similar reduction in the microhardness. The results demonstrated that enzymes in human saliva are capable of softening the surface of dimethaerylate polymers presumably by inducing a hydrolysis of methacrylate ester bonds. The mechanical removal of a surface layer softened by hydrolases will expose a new surface layer to enzymatic attack. The enzymatic softening may thus contribute to the in vivo wear of composite restorations.     

Learning Disabilities in Children: Significance of Low-Level Lead-Exposure and Confounding Factors

Abstract. The hypothesis that low-level lead absorption is a risk factor for learning disabilities in school children was examined in the municipality of Aarhus, Denmark. During 1982-1983, a total of 1302 children in the first grade (54 % of the eligible population) delivered shed deciduous teeth. The lead concentration in the circumpulpal dentin was used as an indicator of the cumulated lead absorption, and 200 cases (high-lead) and controls (low-lead) were selected, and matched for socioeconomic group and gender. The parents were interviewed regarding the child's development and past medical history. Possible confounders were identified and controlled for in a logistic multivariate model. The influence of lead absorption became statistically signincant only after exclusion of the children with proven medical risk factors, thereby the adjusted odds ratio in the weighted analysis was changed from 2.2 to 4.3. Thus, in a Scandinavian low-level lead-polluted area, lead absorption appears to be a risk factor for learning disabilities.     

Allergy tests against formaldehyde, cresol, and eugenol in children with formocresol pulpotomized primary teeth

abstract – One hundred and twenty-eight children in the age range 5—14 years with formocresol pulpotomized teeth were tested for sensitivity against formaldehyde, eugenol, and cresol using the patch test. The number of treated teeth on each child varied from one to six and the time between the pulpotomy and patch test varied from 2 months to 8 years. None of the children showed positive results.     

Pulp condition of successfully formocresol-treated primary molars

abstract — The aim of the study was to assess the state of the pulp of primary teeth successfully treated by formocresol pulpotomy. Nineteen teeth, all of them with clinically and radiographically successful treatments, were extracted 3–24 months after treatment. The pulpal condition had changed in all the teeth. Inflammatory reaction or necrosis was observed in all teeth. Dentinal resorption followed by apposition of hard tissue were common findings. In the teeth with vital tissue only in the apical area, the tissue had minor or no signs of inflammation. Microorganisms could be demonstrated in the necrotic tissue in one tooth. The wide range of pulpal conditions observed indicated that there was no typical tissue reaction to formocresol even though treatment was clinically successful. The present study confirms that the formocresol method should be regarded only as a means to keep primary teeth with pulp exposures functioning for a limited period of time.     

Social Conditions of Temporal Lobe Epileptics in Denmark

The 79 patients with temporal lobe epilepsy treated by resection of the temporal lobe at Rigshospitalet, Copenhagen, were followed up. Most patients belonged to the lower social levels of the population, more were born out of wedlock and more were institutionalized. Although they achieved a higher level of education than the average, fewer were employed outside the home or studying or performing domestic duties, more were unmarried or divorced, and their social level was lower than their parents'.     

Haemostatic and complement changes in a family with 'allergic' disorders

A family with allergic manifestations, haemostatic disturbances, total absence of haemolytic activity of the complement system and low IgG levels is described. It is suggested that this functional abnormality of the complement system and the decreased level of immunoglobulin G may be due to immune complex reactions.     

Phonological development in very‐low‐birthweight children: an exploratory study

Aim Very‐low‐birthweight (VLBW; birthweight <1500g and/or gestational age <32wks) children are at risk for speech problems. However, there are few studies on speech development in VLBW children at an early age. The aim of this study was to investigate phonological development in 2‐year‐old VLBW children. Method Twenty VLBW children without major neurosensory impairment (7 males, 13 females; mean birthweight 971g, SD 315; mean gestational age 28wks, SD 1.81) and 20 term children (7 males, 13 females; mean birthweight 3503g, SD 416; mean gestational age 40wks, SD 1.26) were compared on measures of phonological development derived from 20‐minute spontaneous speech samples of standardized mother–child play interaction as well as on standardized tests of cognitive and psychomotor development, language, and behaviour. Results VLBW children had significantly fewer acquired consonants (median 9, p=0.02) and a significantly lower phonological mean length of utterance (pMLU; median 4.1, p<0.01) than term children (median acquired consonants 10, median pMLU 5.0). Interpretation This study provides evidence for poor phonological development in even healthy VLBW children, compared with term‐matched children, independent of their cognitive, psychomotor, and language development, and their behavioural functioning.