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Biomedical subjects

M A Hansen

Publications and source records attributed to M A Hansen.

3 recordsLinked to original sources
PubMed1979

An electromyographic and roentgen cephalometric study of occlusal morphofunctional disharmony in children.

In a sample of children with dual bite and symptoms in the masticatory system, the activity of the anterior temporal and masseter muscles was studied electromyographically during clench and light tapping in the posterior occlusal contact position and centric occlusion and in protrusive bite on the incisors. The findings indicated that the optimal muscle function during maximal clench and tapping with displayed in the posterior occlusal contact position, which in the present subjects was situated, on the average, 0.5 to 1 mm. anterior to the centric jaw relation. It should therefore be recommended that, in orthodontic treatment of children with dual bite, the intercuspal position (centric occlusion) should be established in the posterior occlusal relationship. This is in accordance with the opinion of several authors who have emphasized the use of the retruded contact position (the centric jaw relation) as key reference position in orthodontic treatment and occlusal rehabilitation. These authors have further emphasized the importance of stable occlusal contacts in centric relation, centric occlusion, and the various jaw excursions in obtaining and maintaining a harmonious function between the dentition, the temporomandibular joints, and the neuromuscular system.

Adolescent↗
PubMed1976

Nutritional deficiency, immunologic function, and disease.

Several experiments conducted by our group over a period of 6 years have shown that nutritional stress, especially protein and/or calorie deprivation, leads to many, often dramatic, changes in the immune responses of mice, rats, and guinea pigs. Chronic protein deprivation (CPD) has been shown to create an enhancing effect on the cell-mediated immune responses of these animals. Humoral responses under CPD conditions were most often found to be depressed, but sometimes were unaffected, depending on the nature of the antigen employed. Chronic protein deprivation, consistent with the pattern just mentioned, improved tumor immunity by depressing production of B-cell blocking factors, and, in at least one instance, resistance to development of mammary adenocarcinoma in C3H mice was associated with evidence of increased numbers of T suppressor cells. Profound nutritional deficits (less than 5% protein per total daily food intake) depressed both cellular and humoral immunity. Early, though temporary, protein deprivation caused a long-term depression of both cellular and humoral immunity also, with the humoral component being the first to recover. Manipulation of protein and calories was found to have a profound effect on certain autoimmune conditions. Diets high in fat and low in protein favored reproduction but shortened the life of NZB mice, whereas diets high in protein and low in fat inhibited development of autoimmunity and prolonged life. Chronic moderate protein restriction permitted NZB mice to maintain their normally waning immunologic functions much longer than mice fed a normal protein intake. Further, the low-protein diet was associated with a delay in development of manifestations of autoimmunity. Decreasing dietary calories by a reduction of fats, carbohydrates, and proteins more than doubled the average life span of (NZB X NZW)F1 mice, a strain prone to early death from autoimmune disease. Histopathologic studies using immunofluorescent microscopy revealed that the development of the renal lesions caused by the deposition of antigen-antibody complexes, which is so characteristic of these mice, was markedly delayed.

Anemia, Hemolytic↗