New developments in orthopedic surgery

Several examples of newly developed concepts and techniques have been described. Better results in congenital dislocation of the hip are being achieved by early diagnosis in the infant and the Salter innominate osteotomy in the older child. Halo-femoral traction has been developed as an adjunct in the treatment of severe scoliosis. Compression stress applied to fractures provokes rapid healing. Early active exercises in joint fractures enhance the functional result. New approaches to the intervertebral disk are being used. The externally powered prosthesis is an example of collective effort from diverse scientific areas. Research activities tend to relate more directly to clinical problems. These and many advances not mentioned are manifestations of the continuing maturation of orthopedic surgery as a surgical specialty.

Onchocerciasis in Kenya 9, 11 and 18 years after elimination of the vector

Elimination of the onchocerciasis vector Simulium neavei through larvicidal operations in focal areas of Kenya in 1946, 1953, and 1955 achieved complete interruption of transmission. Since no treatment was administered to the infected population, the areas provided an opportunity for studying the natural course of the infection in man in the absence of reinfection, with particular emphasis on its average duration and the effect of duration of exposure to the infection. In a follow-up survey conducted in 1964 in four focal areas, approximately 2000 people were examined parasitologically and clinically; slightly over half this group were also given a thorough ophthalmological examination. The results showed that, 11 years after interruption of transmission, live Onchocerca volvulus adults were present in nodules and microfilariae were present in the skin; after 18 years, however, microfilariae were no longer found in the skin. Assuming that in hyperendemic areas parasites are acquired until shortly before interruption of transmission, it can thus be postulated that O. volvulus worms lose their reproductive potentiality after 16 years or possibly earlier. A comparison of recent microfilarial rates with adjusted rates found in earlier surveys seems to indicate that the onchocercal infection, after interruption of transmission, follows a straight regression line, theoretically reaching zero after about 13-17 years.

Teratogenic action of the thyroid stimulating hormone and its interaction with trypan blue

The role that the thyroid gland may play in embryonic development has been under investigation for many years. A direct relationship between thyroid gland function and development is best illustrated in the amphibia (see Kollros, 1961, for pertinent literature). Attempts to demonstrate a similar influence of thyroxin on development in mammals has led to controversial results, in part due to the difficulty of separating the metabolic from the possible developmental effects of the hormone. In order for thyroxin to exert a direct effect upon the mammalian embryo it must cross the placenta. The bulk of the evidence seems to favor the viewpoint that the placenta is rather impermeable to thyroxin during the early stages of gestation and that this permeability increases near term. This is apparently true of the rabbit and man (Osorio & Myant, 1960) and the rat (Hamburgh, Sobel, Koblin & Rinestone, 1962; Roy & Kobayashi, 1962).

Experimental Study of the Effects of Potassium Bichromate on the Monkey's Kidney

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Glomerular Changes in the Kidneys of Rabbits and Monkeys Induced by Uranium Nitrate, Mercuric Chloride and Potassium Bichromate

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