The dentate gyrus in hypoglycemia: pathology implicating excitotoxin-mediated neuronal necrosis

A detailed light- and electron-microscopic study of the damage to the rat dentate gyrus in hypoglycemia was undertaken, in view of the previously advanced hypothesis that hypoglycemic nerve cell injury is mediated by a released neurotoxin. The distribution of neuronal necrosis showed a relationship to the subarachnoid cisterns. Electron microscopy of the dentate granule cells and their apical dendrites revealed dendrosomal, axon-sparing neuronal pathology. Dentate granule cells were affected first in the dendrites in the outer layer of the stratum moleculare, sparing axons of passage and terminal boutons. Subsequently, the neuronal perikarya were affected, and Wallerian degeneration of axons followed. Cell membrane abnormalities preceded the appearance of mitochondrial flocculent densities and degradation of the cytoskeleton, and are suggested to be early lethal changes. The observed early dendrotoxic changes, and the dendrosomal, axon-sparing nature of the lesion implicate an excitotoxin-mediated neuronal necrosis in hypoglycemia.

["Polycystic disease": evaluation of the value of nuclear medicine. A case report (author's transl)]

The value of examining "polycystic disease" by means of nuclear medicine is being demonstrated -- using one case as an example. Nuclear medicine studies, because of their inherent capability of evaluating both morphology and function at the same time, seem to place this method ahead of others, including ultrasound and C.T.

[Status of dental preventive efforts in Switzerland]

Regarding schools, the first endeavours of preventive dentistry based on the results of modern scientific results were made in the early fifties in the Canton of St. Gall. Great efforts have been made since then and it is impossible to keep track of all activities. At the schools it is the teachers on one hand and specialized or lay auxiliary personnel on the other who organize and perform supervised toothbrushing exercises with fluorides. In Switzerland there are now some 30 full-time positions for auxiliaries charged with preventive measures at Kindergarten or school. An estimate of the population reached by the various methods of prevention is presented. The costs of prevention are but a small fraction of the cost of conservative treatment. In the majority of the private dental offices prevention is part of the activity, but with varying intensity. As to public clinics, the preventive programm run by the Volkszahnklinik Basel is most advanced. It is important that prevention is introduced in all regions of Switzerland and that it reaches the children of all ages. The future depends strongly on the availability of auxiliary personnel working at the schools and in the dental offices.

[Prophylactic measures in general dental practice. An inquirly on their state and frequency]

Questionnaires concerning the type of oral examinations and preventive measures used in private practice were sent to 500 randomly selected dentists in the german-speaking part of Switzerland. 300 were returned completed, the majority of these anonymously. In the examination of new patients, bite-wing radiographs were the most commonly used diagnostic aid. This was reported in 60% of the offices--more often by younger than by older pracitioners, more frequently in urban than in rural offices and more often in surgeries treating less than 12 patients a day. Concerning oral restauration itself, the most frequently frequently reported procedures were the treatment of clinically visible carious lesions, polishing and the replacement of defective fillings. A broad spectrum of prophylactic oral hygiene aids were reported. Toothbrush and dental floss combined with oral hygiene instruction, however, were still the most commonly used. There was considerably correlation between the type of prophylactic acids used and the type of the dental practice. According to the questionnaires, fluoride prophylaxis is very regulary carried out and recommended. The ways in which this fluoride prophylaxis is carried out differs from practice to practice. Nutritional prophylaxis counseling was considered in the majority of the offices irrespective of the type of office. Relatively little emphasis was placed upon cooperation of the patient. From the questionnaries we calculated a need for about 550 DH for Switzerland. Younger dentists mentioned this need relatively moe often than older practitioners. A recall system was used in 70% of the practices, whereby annual and semi-annual intervals were reported with equal frequency. It is obvious that the emphasis placed upon prevention is not the same in all practices. This statement is valid also for the carious and periodontal diagnostic measures utilized. Much work as well as maybe a certain resignation resulting from previous failures may prevent the dentist from instituting more preventive measures in his practice. It is obvious that the graduates of the new dental hygiene school can help in this regard. However, because as yet these new graduates cannot supply even one half of the 550 required hygienists, it is discussed whether or not dental chair-side assistants with special training could motivate our patients toward a more satisfactory oral hygiene.