Cohort Profile: the HUNT Study, Norway.

The HUNT Study includes large total population-based cohorts from the 1980ies, covering 125 000 Norwegian participants; HUNT1 (1984-86), HUNT2 (1995-97) and HUNT3 (2006-08). The study was primarily set up to address arterial hypertension, diabetes, screening of tuberculosis, and quality of life. However, the scope has expanded over time. In the latest survey a state of the art biobank was established, with availability of biomaterial for decades ahead. The three population based surveys now contribute to important knowledge regarding health related lifestyle, prevalence and incidence of somatic and mental illness and disease, health determinants, and associations between disease phenotypes and genotypes. Every citizen of Nord-Trøndelag County in Norway being 20 years or older, have been invited to all the surveys for adults. Participants may be linked in families and followed up longitudinally between the surveys and in several national health- and other registers covering the total population. The HUNT Study includes data from questionnaires, interviews, clinical measurements and biological samples (blood and urine). The questionnaires included questions on socioeconomic conditions, health related behaviours, symptoms, illnesses and diseases. Data from the HUNT Study are available for researchers who satisfy some basic requirements (www.ntnu.edu/hunt), whether affiliated in Norway or abroad.

Occurrence of injuries in a defined population.

A 1-year study of all registered accidents was carried out. All patients treated for an injury at the Trondheim University Hospital, Norway, were recorded. This is the only institution in the region treating injuries. Hence, this is a total injury registration in a defined population. The incidence rate was 114 injuries per 1000 inhabitants. Home accidents were the most common type. Accidents occurring at institutions, in traffic areas and at home caused the longest hospitalization. Most of the injuries were minor; 0.4 per cent of the accidents were fatal. Traffic accidents and home accidents were responsible for the highest percentage of fatal accidents. The demand for preventive measures and reduction of accidents has been based on mortality rates in comparable studies. The mortality rate is well reported for most of the civilized world but this does not tell us anything about the morbidity rate due to accidents. By reducing the accidents needing the longest hospitalization, the economic consequences for the national health system would also be decreased.

New malignancy grading is a better prognostic indicator than Broders' grading in oral squamous cell carcinomas.

The prognostic value of histopathologic grading of oral squamous cell carcinomas (SCC) has varied from not any to highly significant. We have retrospectively studied all (130) SCCs registered in Norway 1963-72 in the buccal and maxillary alveolar mucosa. From 68 of these cases biopsy specimens of acceptable quality were obtained. Broders' method of grading was compared with a modification of a recent malignancy grading system recommended by Anneroth et al. which was performed only within the histologically most invasive areas of the tumors. Cox's multivariate survival analyses showed that this grading in the invasive sites had highly significant prognostic value. Broders grade had no prognostic value. The stage of tumor had also prognostic value. These highly significant results indicate that the histologically invasive areas may be primarily responsible for the clinical behavior of the tumor, and this may be of importance for the choice of therapy for oral SCC.

Autoradiographic investigation of effects of high-dose colchicine on dentinogenesis in rat incisors.

Twelve female Wistar rats received 1.5 mg/kg of colchicine (CLC) intravenously. Control animals were similarly injected with isotonic saline solution. The animals were killed 5 h, 24 h, 3 days and 7 days after injection. Ninety minutes prior to sacrifice, all animals received an intraperitoneal injection of 3H-proline. Autoradiograms of maxillary incisors showed that CLC increased the retention of the labeled precursor in the odontoblasts. It was also shown that the odontoblasts in the different sectors of the rat incisor present different sensitivities to the CLC action.

Dental features in congenital persistent renal tubular acidosis of proximal type.

The dental features in a hitherto unknown type of renal tubular acidosis (capillary blood pH 7.07-7.15) of proximal type are reported. The patient presented agenesis of three second premolars, delayed development and eruption of permanent teeth, delayed shedding of the primary dentition and severe enamel hypoplasia of the permanent teeth. Apart from exceptionally thin enamel, histologic, fluorescent and polarization microscopic and microradiographic investigation of three primary teeth did not reveal unusual findings. The changes are most probably due to a generalized, acidosis-induced defect in several highly differentiated ectodermal tissues.

Colchicine's effects on rat incisor odontoblasts and dentinogenesis.

Colchicine (CLC) in doses of 0.5 and 1.5 mg/kg was administered to 40 female Wistar rats in two equal groups. The animals were sacrificed after 5 h, 24 h, 3 d and 7 d, and the effects of CLC on pulp, odontoblasts and dentin in the continuously growing incisors were studied. With the lowest dose a few arrested mitoses were observed in the germinative part of the pulp after 5 and 24 h. With the highest dose an increasing number of mitoses were observed in the germinative part of the pulp after 5 and 24 h. More incisally the odontoblasts were pale, swollen and granulated after 5 h, and necrotic and disintegrated after 24 h. After 3 and 7 d dentinal derangements, consisting of moderately and severely irregular dentin, osteodentin and a niche-like defect in the labial dentin, were seen. Labially one or two incremental lines traversed the dentin from the apical to the incisal part of the incisors.

Autoradiographic investigation of dentin production in rat incisors after vincristine administration.

0.7 mg/kg VCR was administered intravenously to nine rats in three experimental groups. One hour after VCR injection the animals were injected with 3H-proline. The animals were sacrificed 1.5, 5 and 24 h after the VCR administration, and by comparison with nine control animals similarly injected with sodium chloride solution and 3H-proline, it was shown that VCR causes an early, intracellular retention of labeled proline in the odontoblasts, an abnormal intracellular distribution of labeled material and a generally decreased secretion of dentinal matrix from the odontoblasts in the maxillary incisors. The severity of the effects were shown to vary in different parts of the incisors.

Autoradiographic investigation of proliferative responses in rat incisor pulp after vincristine administration.

-0.7 mg/kg VCR was given to nine rats in three experimental groups. Twenty-three hours after VCR injection the animals were injected with 3H-thymidine. The animals were sacrificed 24, 48 and 72 h after the VCR injection, and by comparison with nine control animals similarly injected with sodium chloride solution and nucleotide, it was shown that VCR causes a delayed migration of pulp cells from the proliferative pool and a small but distinct inhibition of the incisal growth of the incisors. The growth inhibition corresponded to the normal growth over a 24-h period in non-VCR-injected animals.

Long-term effects of colchicine on dentinogenesis in rat incisors.

Colchicine in doses of 0.5, 1.0 and 1.5 mg/kg was administered to 15 rats divided in three experimental groups. Histomorphologic investigation of the maxillary incisors after 2 weeks revealed; 1) alterations in the odontoblasts mainly related to size, shape, polarity and staining properties, and 2) presence of irregular dentin separated from normal dentin by one or two incremental lines. The dentinal irregularities were dose-dependent and consisted of twisting of the dentinal tubules, globular formations and cellular inclusions in addition to niche-like defects.

Vincristine's effect on dentinogenesis in rat incisor.

Vincristine was administered to 60 rats in four groups in doses of 0.1, 0.3, 0.5 and 0.7 mg/kg. Histomorphologic investigation of the dentin and odontoblasts in the maxillary incisors after 1, 2 and 3 weeks revealed a moderate to severe disturbance of dentin production in some parts of the incisors. In some of the affected areas the effect seemed to be reversible in that normal-appearing dentin was found pulpal to the dentinal derangements after 2 and 3 weeks. The distribution and severity of the lesions were similar to those previously observed 3 days after injection of the same doses of vincristine.

Effect of vincristine on odontoblasts in rat incisor.

Vincristine in doses of 0.1, 0.3, 0.5 and 0.7 mg/kg was administered to 60 rats in four groups. Histomorphologic investigation of the odontoblast population in the maxillary incisors revealed dose-dependent reactions consisting of (1) swelling of the odontoblasts and an accumulation of abnormal mitotic cells in the germinative parts of the pulp after 5 h, (2) a supervening necrosis and destruction of some odontoblasts and of the mitotic cells after 24 h, and (3) after 3 d, a reversal to normal structure in some parts of the odontoblast population, but a further development of the vincristine-induced changes, with severe cellular derangement and irregular predentin production, in others.

Mixed tumor of skin.

A 40-year-old white male consulted his dentist because of a mass in the upper lip to the right of the midline. The patient stated that the lesion had been present and slowly enlarging for at least the pat 10 years. A mass that appeared to be about the size of a hazel nut was apparent to direct visualization and it produced an elevation of the lip surface. On palpation, the mass was found to have a firm rubbery texture and to be freely movable. The history of slow growth of an apparently well delineated mass over a lengthy period of time, together with a lack of fixation to the surrounding tissues of the lip was considered indicative of a benign lesion. The mass was extirpated using an intraoral approach under local anesthesia.

Carcinomas of intraoral salivary glands.

Of 44 intraoral salivary gland tumours received by the Department of Pathology, Dental Faculty, University of Oslo over the last 20 years, 21 (approx. 48%) were classified as carcinomas. Of these, the adenocarcinomas constituted the largest group, but because some of them bore a certain likeness to adenoid cystic carcinomas and to mucoepidermoid tumours, we believe that transitions exist between these groups of neoplasms. The material is thought to reflect the daily practice of oral surgeons and general dental practitioners, and we think it important to emphasize that approximately every second tumour in this series was malignant.

Aberrant salivary gland tissue in the anterior mandible.

Salivary gland tissue inclusions in the posterior part of the mandible are not rare. Inclusions in the anterior portion, however, are very unusual, and the case presented here brings the number of reported cases up to a total of seven. The aberrant gland appeared on a panoramic radiograph as a radiolucency judged to be a periapical lesion on the right mandibular second premolar.

The effect of vincristine on dentinogenesis in the rat incisor.

A preliminary report on the histomorphologic effects of vincristine on rat incisor dentinogenesis is presented. Niche-like areas of osteodentin and a faint incremental line in the dentin were the main derangements observed after single injections of the drug. The severity of the lesions was dose-dependent.