TARDBP mutations are not a frequent cause of ALS in Finnish patients

In previous studies 1-3 % of ALS patients have TARDBP mutations as the cause of the disease. TARDBP mutations have been reported in ALS patients in different populations but so far there are no studies on the frequency of TARDBP mutations in Finnish ALS patients. A cohort of 50 Finnish patients, 44 SALS and 6 FALS patients, were included in the study. Genomic DNA was extracted from venous blood or muscle tissue and a mutation analysis of TARDBP was performed. No definitely pathogenic mutations could be identified in TARDBP in our patient cohort. However, two previously unknown variations were found: one silent mutation in exon 2 and one relatively deep intronic single nucleotide insertion in intron 5. In addition, two previously known non-pathogenic polymorphisms in intron 5 were detected. The size of our cohort is obviously not large enough to conclusively exclude TARDBP mutations as a very rare cause of ALS in Finland. However, based on our results TARDBP mutations do not appear to be a frequent cause of familial or sporadic ALS in Finland.Key words: Amyotrophic lateral sclerosis, mutation screening, TARDBP     

Resorption of autotransplanted human teeth: a retrospective study of 291 transplantations over a period of 25 years

Summary. An assessment was made of the postoperative fate of 291 autotransplanted human teeth, carried out in the period from 1955 to 1980, with special reference to root resorption.
Root resorption was found to be the major cause of graft loss ( P < 0.0001), During the observation period, inflammatory resorption (IR) was diagnosed in 94 cases, leading to graft loss in 39 cases (mean survival time for grafts with IR was 7.2 years). Replacement resorption (RR) was found in 52 cases, leading to graft loss in 19 cases during the observation period, but with a considerably lower intensity of graft loss than in the IR group (mean survival time for grafts with RR was 12.0 years).
The influence of several pre- and peroperative factors on the appearance of the two types of root resorption following autotransplantation was investigated. Premolars were found to be significantly less affected by IR compared with molars, and canines were more frequently affected by IR (64 per cent). The younger the patient, and especially the earlier the stage of root development of the donor tooth, the less IR, although pulp obliteration occurred more frequently in the early graft developmental stage. Ectopia of the donor tooth seemed to be followed by an increased frequency of IR and RR after transplantation.
Extraoral storage induced both IR and RR. Peroperative endodontic treatment should be avoided, although endodontic treatment, in general, seemed to have an arresting influence on IR. Marginal bone loss seemed to affect fully developed grafts more than grafts transplanted at an earlier stage but, in general, root resorption was found to be the most relevant complication of autotransplanted human teeth.     

Mercury concentrations in blood from Danish dentists

Abstract — Blood samples from a group of 130 dentists and a control group of 40 blood-donors were analyzed by cold vapor atomic absorption spectrophotometry in order to evaluate the extent of mercury exposure. The median blood concentration of mercury was 4.0 (range: 1.2–19.2) μg/1 for dentists and 2.0 (1.1–4.6) μg/1 for controls (2 P <0.01). Practice characteristics obtained in a questionnaire showed no statistically significant relationship to blood mercury, but 49 dentists having one or more fish meals per wk, had a median concentration of mercury, which was 47% higher than dentists seldomly consuming fish (2 P <0.01). It was concluded that none of the examined dentists had blood concentrations above the level (35 μg Hg/1) associated with the hygienic threshold limit.     

One-year study of the efficacy of a dentifrice containing zinc citrate and triclosan to maintain gingival health

Abstract – In a previous study we demonstrated that gingival health could be maintained in a group of highly motivated nurses using a dentifrice containing a zinc salt and triclosan. We have now investigated the effect of the experimental dentifrice on a group of less motivated men. One hundred and three male students were given oral hygiene instruction (OHI) and their teeth were professionally cleaned. For each individual, both the instruction and cleaning were completed in a single 15-min period. Two balanced groups were formed, based on the prestudy plaque levels and gingival bleeding. One group used the experimental dentifrice for 12 months, while the other used a control. Results were assessed after 6 months, and after 12 months. As a result of the OHI, plaque and gingival bleeding were reduced at the end of the prestudy period. This improvement was not maintained by the control group even for 6 months. In contrast, the test group exhibited significantly lower plaque levels and higher standard of gingival health throughout the 12 months. Reassessment of available participants 6 months after the study showed that gingival health in both groups had returned to its prestudy condition. The lower observed standard of gingival health in the test group after ceasing to use the experimental dentifrice further supports the conclusion that this dentifrice can contribute to an oral care program.     

In vivo antibacterial effect of tin on the oral microflora

Abstract – The antibacterial effect of oral rinses with stannous fluoride and stannous chloride solutions, and of the use of a toothpaste containing stannous fluoride and stannous pyrophosphate was tested by recording the bacterial viable counts on the oral mucous membrane. Stannous chloride had no antibacterial effect, while stannous fluoride drastically reduced the viable counts up to 4 h. Calculations demonstrated that 25% of the tin content in 10 ml rinsing solutions was retained in the mouth, and analyses showed a raised tin level in saliva up to 4 h after rinsing or toothbrushing. It is suggested that most of the retained tin is bound to the oral mucosa.     

Estimation of B- and T-Lymphocytes in Lymphoid Tissue by Means of Photometry and 51Cr Labelled Marker Erythrocytes

Some new techniques for estimating B- and T-lymphocytes in lymphoid tissue are introduced: The density of marker erythrocytes on closed chamber incubated sections was estimated by the light transmission in relation to the number of the respective lymphocyte subpopulation, measured on suspensions of eluted lymphocytes. Using ⁵¹Cr labelled marker erythrocytes, the number of adsorbed marker erythrocytes per lymphocyte could be estimated from the γ-irradiation of the section. The number of lymphocytes in the section was determined by the amount of protein in the section compared with the protein amount of a tissue specimen of known wet weight and known lymphocyte content. Furthermore, the number of adsorbed marker erythrocytes per rosette in suspensions of eluted lymphocytes was estimated by means of radioactively labelled marker erythrocytes.     

Diabetes mellitus among first- and second-deǵree relatives of early onset diabetics

This study is based on a material consisting of all first-degree relatives and a group of second- degree relatives (all nieces and nephews) of 187 propositi affected by early onset (i.e. at or prior to 20 years of age) diabetes mellitus, diagnosed before 1946. The incidence of diabetes among the different groups of relatives is expressed as the risk of developing the disease at specified ages. It is concluded that the risk of siblings or children of early-onset diabetics developing the same disease is about ten times that of a normal population chosen for comparison, whereas the risk of siblings developing diabetes later in life does not differ from this normal population. On the basis of the data presented here, combined with reanalyses of previously published data from other authors, it is concluded that early onset and late onset diabetes cannot have an identical genetic background. The initial study was proposed by Professor Mogens Hauge, M.D., to whom we are greatly indebted for his valuable help through all phases of the study. We would like to thank Dr Jacob E. Podsen, M.D., for giving access to the files of the Steno Memorial Hospital and for valuable advice concerning clinical problems. We would also like to thank the Danish National Registries and especially Miss Julie Konow, Registry of the Municipality of Copenhagen. During the initial study B. D. received a scholarship from the University of Copenhagen, and the follow-up study has been made possible by support from the Danish Diabetic Association (Landsforeningen for Sukkersyge) and Dr. med. Erik Garde og Elisabeth Gardes Legat.     

Localization of Mercury in CNS of the Rat III. Oral Administration of Methylmercuric Chloride (CH3HgCl)

The distribution and cellular localization of mercury in thein situ brain and upper cervical spinal cord of adult Wistarrats were studied at various time intervals after oral administrationof methylmercuric chloride (CH₃HgCl; 20 mgxliter^–). Coronalsections of the brain and transverse sections of the cervicalspinal cord were prepared for visualization of the mercury bythe autometallographic silver-enhancement method. Followingmercury administration there was a latent period before themenal appeared in the tissue. Mercury staining was first detectedafter 10 days in cell bodies of five specific areas of the brainstem: the mesencephalic nucleus of the trigeminal nerve, thered nuclei, the ventral cochlear nucleus, the superior vestibularnucleus, and the nucleus reticularis pontis caudalis. After28 days of treatment, a fairly even distribution of mercurywas seen in the brain and spinal cord. Longer periods of treatmentcaused no further increase in the density of mercury withinthe stained cell bodies. In cerebral cortex, staining commencedin piriform and entorhinal cortices. This was followed by stainingin neurons of lamina III in the isocortex and ultimately alllayers were stained after 28 days of treatment. After 20 daysof treatment, mercury deposits in the cerebellar cortex wererestricted to Purkinje cells, Golgi epithelial cells, and Golgicells, while in the spinal cord the majority of mercury waslocated in the anterior horn motoneurons. Scattered ependymalcells and epithelial cells of the choroid plexus also exhibitedmercury staining. The principal target cells were neurons followedby the glial and ependymal cells. Ultrastructurally, the bulkof detectable mercury was localized in lysosomes.